What are the different operators available in SQL? For example, char(10) can only store 10 characters and will not be able to store a string of any other length whereas varchar2(10) can store any length i.e 6,8,2 in this variable. These are some basic but very essential questions an Sql professional should know. Now, let’s see an example for the INTERSECT operator. Practice 25 Data Migration Interview Questions with professional interview answer examples with advice on how to answer each question. The only disadvantage of Stored Procedure is that it can be executed only in the database and utilizes more memory in the database server. It takes a string as an argument and returns it by converting it into uppercase. I guess if you know SQL Server you can find many ways to figure things out. Tables store data that represents one type of entity. Q32. Let us suppose, we have two tables Table A and Table B. What is a Cursor in SQL and how to implement it? Learn about interview questions and interview process for 62 companies. And for schema Migration we can use Generate Script Wizard. In a subquery, the outer query is called as the main query whereas the inner query is called subquery. to accomplish multiple operations such as selects/inserts/updates/deletes. SQL Server Migration Tutorial from Coding compiler | SQL Server DBA Tutorial – Part 7, this blog is the seventh tutorial in the series, here you are going to learn about how SQL server migration works. Explicitly by specifying NULL keyword in the VALUES clause. Composite-column Indexes: A composite-column index is an index created for two or more columns of the table. Following are the different types of collation sensitivity: These variables can be used or exist only inside the function. What are SQL Operators and how do they work? 1. Inner Join basically gives us those records that have matching values in two tables. For example – A bank database has a customer table to store customer information. You can make these challenges predictable and less painful through diligent preparation and collecting the necessary information before you start. What is the difference between clustered and non clustered index in SQL? use SQL. Your email address will not be published. So, if we have a foreign key, then we have to use the DELETE command. AUTO INCREMENT keyword can be used in Oracle and IDENTITY keyword can be used in SQL SERVER. A database is a structured collection of data. Position indicates the starting location for overwriting the string. Some of the advantages are: Apart from this SQL Interview Questions Blog, if you want to get trained from professionals on this technology, you can opt for a structured training from edureka! It is a programming language for a database that uses SQL. Primary Key In SQL : Everything You Need To Know About Primary Key Operations, Foreign Key SQL : Everything You Need To Know About Foreign Key Operations. Syntax: This function returns the string in uppercase. A stored procedure is a prepared SQL code that can be saved and reused. Definition, Types and Components. Then select the server from the Tools menu. Let’s create an Employee table where column names are ID, NAME, DEPARTMENT, and EMAIL. Aggregate functions are used to evaluate mathematical calculation and returns a single value. In this SQL Interview Questions blog, I will introduce you to the most frequently asked questions on SQL (Structured Query Language). 2) Extensibility and support for SQL 3) Database validation and flexible API 4) Procedural languages and MVCC 5) Client server and WAL. A subquery is a query inside another query where a query is defined to retrieve data or information back from the database. Let’s say, we have executed rollback before committing changes, but in the case of truncate, it is not possible because there is no log file generated (for understanding, you can assume truncate to be something like ‘Shift + Delete’). Data Engineer Interview Questions and Answers: SQL Workload Migration to Microsoft Azure Database Platforms August 13, 2020 by Ahmad Yaseen In this article, we will discuss a number of questions that you may face when being interviewed to a Microsoft Azure Data Engineer position. Each consecutive normal form depends on the previous one.The first three normal forms are usually adequate. Unique constraints ensure that all the values in a column are different. We have to copy this data into another table. Understanding SQL Data Types – All You Need To Know About SQL Data Types, SQL Tutorial : One Stop Solution to Learn SQL, DBMS Tutorial : A Complete Crash Course on DBMS, CREATE TABLE in SQL – Everything You Need To Know About Creating Tables in SQL. The Join clause is used to combine rows from two or more tables based on a related column between them. What is Database Testing and How to Perform it? Constraints are used to specify some sort of rules for processing data and limiting the type of data that can go into a table. SELECT * FROM Students where ROLL_NO BETWEEN 10 AND 50; SELECT * FROM students where ROLL_NO IN (8,15,25); Q38. It adds the redundant data into a table by incorporating database queries that combine data from various tables into a single table. For example: Table: StudentInformation Field: Stu Id, Stu Name, Stu Marks. This also supports faster execution when compared to executing multiple queries. In the below employee table, say, we want to perform multiple operations on the records with gender ‘Female’. We can consolidate several SQL statements into a stored procedure and execute them whenever and wherever required. The sample of constraints are: Apart from this SQL Interview Questions blog, if you want to get trained from professionals on this technology, you can opt for a structured training from edureka! It performs an UPDATE if a row exists, or an INSERT if the row does not exist. The SQL query above will delete the rows, where the name fields are duplicated, and it will retain only those unique rows in which the names are unique and the ID fields are the lowest. Having Clause is only used with the GROUP BY function in a query whereas WHERE Clause is applied to each row before they are a part of the GROUP BY function in a query. SQL functions are used for the following purposes: This statement allows conditional update or insertion of data into a table. Learn how to use SQL SELECT with examples. It cannot have NULL values, and it must contain unique values. Our SQL Interview Questions blog is the one-stop resource from where you can boost your interview preparation. Verification of the outgoing data from the other query functions. A field refers to the number of columns in a table. The redundancy and inconsistent dependency can be removed using these rules to make it more flexible. Hence, such systems are generally used for data mining or maintaining aggregated historical data, and they are usually used in multi-dimensional schemas. In SQL, there is a built-in function called GetDate() which helps to return the current timestamp/date. It also defines integrity constraints to enforce business rules on the data when it is entered into an application or a database. Clustered index is used for easy retrieval of data from the database and its faster whereas reading from non clustered index is relatively slower. Now, let’s see how to set a default constraint. Now, we will see the major differences between clustered and non-clustered indexes: Now, in this ‘Top SQL Interview Questions’ blog, we will move on to the next question. What is Normalization in SQL and what are its types? What do you mean by table and field in SQL? Top 30 AWS Database Interview Questions. The foreign key constraint prevents actions that would destroy links between the child and parent tables. All the best for your interview! For example, if we assign a default constraint for the E_salary column in the below table and set the default value as 85000, then all the entries of this column will have a default value of 85000 unless no other value has been assigned during the insertion. Click Start> Programs> Microsoft SQL Server and click SQL Enterprise Manager to run SQL Enterprise Manager from the Microsoft SQL Server program group. SSIS Tutorial For Beginners: Why, What and How? For example – UCASE(), NOW() are calculated with respect to string. To check for the consistency of the database, it selects the default table values. Non-Correlated subquery: This query is an independent query where the output of subquery is substituted in the main query. According to research SQL Server, DBA has a market share of about 46%. These variables are the variables which can be accessed throughout the program. MySQL Workbench Tutorial – A Comprehensive Guide To The RDBMS Tool, PostgreSQL Tutorial For Beginners – All You Need To Know About PostgreSQL, PL/SQL Tutorial : Everything You Need To Know About PL/SQL, Top 65 SQL Interview Questions You Must Prepare In 2020, Top 50 MySQL Interview Questions You Must Prepare In 2020, Top 50 DBMS Interview Questions You Need to know. PL/SQL is a procedural and application-oriented language. There are many successive levels of normalization. What do you mean by “Trigger” in SQL? Post-Graduate Program in Artificial Intelligence & Machine Learning, Post-Graduate Program in Big Data Engineering, Implement thread.yield() in Java: Examples, Implement Optical Character Recognition in Python, SQL Essentials Training and Certification, Mock interview in latest tech domains i.e JAVA, AI, DEVOPS,etc, Real time assessment report and video recording. SQL is a declarative and data-oriented language. The distinction between HAVING and WHERE clauses in SQL is that while the WHERE clause cannot be used with aggregates, we use the HAVING clause with the aggregated data. This is a one-stop resource through which you can avail the maximum benefit and prepare for job interviews easily. Now, we will write a query for demonstrating the use of a primary key for the Employee table: A foreign key is an attribute or a set of attributes that references to the primary key of some other table. SQL is one of the most widely used languages. Trigger in SQL is are a special type of stored procedures that are defined to execute automatically in place or after data modifications. Check out the top SQL interview questions asked by recruiters today: Q1. Upgrading SQL Server, interview questions on upgrading sql server, migrating sql server,Upgrading SQL Server Questions and Answers. A view refers to a logical snapshot based on a table or another view. For example: There are three case manipulation functions in SQL, namely: Some of the available set operators are – Union, Intersect or Minus operators. Migrating a Database across platforms. NULL value represents a value which is unavailable, unknown, assigned or not applicable whereas a zero is a number and blank space is a character. There are various relationships, namely: NULL values can be inserted in the following ways: BETWEEN operator is used to display rows based on a range of values in a row whereas the IN condition operator is used to check for values contained in a specific set of values. Go through these top SQL interview questions to learn SQL programming, thoroughly. OLTP: It basically stands for Online Transaction Processing and we can consider it to be a category of software applications that is efficient for supporting transaction-oriented programs. We will now join the table using Self Join: The Union operator is used to combine the result set of two or more select statements. End of the training you will be able to create and administer your own MySQL Database and manage data. Relational Database Management System (RDBMS) is the most common database used across organizations, making SQL a must-have skill. SQL Azure database Interview question for fresher and experienced. In an AWS interview, you may come across basic as well as advanced AWS database interview questions. A Database Management System (DBMS) is a  software application that interacts with the user, applications and the database itself to capture and analyze data. It helps perform the module testing of database functions, triggers, views, and SQL queries. COALESCE function takes a set of inputs and returns the first non-null value. Select SQL Server Configuration Properties, and choose the Security page. It is used for the following reasons: A Stored Procedure is a function which consists of many SQL statements to access the database system. RDBMS is one of the most commonly used databases till date, and therefore, Want to Upskill yourself to get ahead in Career? How would you find the second highest salary from the below table? Thank you for sharing. Consider the customer table given below. Right Join: Right Join returns rows that are common between the tables and all the rows of the right-hand-side table, i.e., it returns all the rows from the right-hand-side table even if there are no matches available in the left-hand-side table. Also, in all technical interviews, 30–40 percent of questions will be from SQL. Required fields are marked *. Here, depending upon some conditions, each row of the table is joined with itself and with other rows of the table. Uniquely identifies a single row in the table. There are various types of Joins that can be used to retrieve data, and it depends upon the relationship between tables. What is the use of DECODE function in SQL? The white box testing method involves the following: The black box test method generally involves interface testing, followed by database integration. What is a Schema in SQL and how to create it? This blog is the perfect guide for you to learn all the concepts related to SQL, Oracle, MS SQL Server and MySQL database. According to my knowledge, we can store the data of any length but it should not exceed 10 characters( if we define char(10)). Basically, it is a database language that is used for the creation and deletion of databases, and it can be used to fetch and modify the rows of a table and also for multiple other things. Q2. Auto increment keyword allows the user to create a unique number to get generated whenever a new record is inserted into the table. With TRUNCATE, we can’t really execute and trigger, while with DELETE we can accomplish a trigger. Q65. State the differences between HAVING and WHERE clauses. I recommend. That is, rows with IDs 5 and 6 are deleted, whereas rows with IDs 1 and 2 are retained. ACID stands for Atomicity, Consistency, Isolation, Durability. 6. Pointers are used for physical data files, Stores data in the leaf nodes of the index, Never stores data in the leaf nodes of the index, By default, the primary key of a table is a clustered index, It can be used with the unique constraint on the table that acts as a composite key, Improves the performance of data retrieval, Should be created on columns used in Joins. What are the differences between the questions from the area of SQL for business analyst positions and for IT jobs? PL/SQL is a block of codes used to write the entire procedure or a function. Q7. What is ACID property in a database? Difference between char and varchar2. What is the need for group functions in SQL? In this blog I am discussing the SQL Server Interview Questions answers on Database Mirroring. There are four types of joins, namely: Inner join: Inner Join in MySQL is the most common type of join. Increasingly, these are SQL-related questions. Clustered index alters the way records are stored in a database as it sorts out rows by the column which is set to be clustered index whereas in a non clustered index, it does not alter the way it was stored but it creates a separate object within a table which points back to the original table rows after searching. The following would select the data on a row-by-row basis: The HAVING clause, on the other hand, operates on aggregated results. The Export and Import utilities are the only method that Oracle supports for moving an existing Oracle database from one hardware platform to another. For example- select * from student where studentname like ‘abc_’. Indexes are used to find all rows matching with some columns and then to skim through only those subsets of the data to find the matches. Excellent questions/answers for beginner to advanced level SQL development covered.nice work and thanks for sharing. Now, let’s understand the default constraint. Please mention it in the comments section of this “SQL Interview Questions” blog and we will get back to you as soon as possible. SQL is a query language that allows you to issue a single query or execute a single insert/update/delete whereas PL/SQL is Oracle’s “Procedural Language” SQL, which allows you to write a full program (loops, variables, etc.) There are two levels  of a constraint, namely: You can fetch common records from two tables using INTERSECT. Then, the Union operator will return the result of the two select statements as shown in Image A U B. Now, let’s see the output when we apply HAVING in the above query. It is used to ensure that the data transactions are processed reliably in a database system. What is SQL? Full Join: Full join returns all the records when there is a match in any of the tables. Here every search_string in the string_expression will be replaced with the replacement_string. Can we join two table which have same data types but different column name ? Data Integrity defines the accuracy as well as the consistency of the data stored in a database. You can fetch alternate records i.e both odd and even row numbers. Check out the top SQL interview questions asked by recruiters today: Q1. INTERSECT Select StudentID from Exam. Normalization is the process of organizing data to avoid duplication and redundancy. Introduction to PostgreSQL Interview Questions and Answers. What is the use of SQL GROUP BY statement? Character manipulation functions are used for the manipulation of character data types. SQL Functions: How to write a Function in SQL? Oracle interview questions !!! Q13. Answer : This feature increases the reliability of the database by logging changes before any changes or updations to the data base. All Rights Reserved. A table refers to a collection of data in an organised manner in form of rows and columns. A clause helps to filter the rows from the entire set of records. Each table can have many nonclustered indexes. Constraints are used to specify the limit on the data type of the table. These calculations are done from the columns in a table. So this brings us to the end of the SQL interview questions blog. These questions are really amazing, to preapre for an interview..Thanks. It is usually used in a GROUP BY clause and whenever GROUP BY is not used, HAVING behaves like a WHERE clause. SQL clause helps to limit the result set by providing a condition to the query. Now, let’s implement it on the SQL server. – An Introduction To Database Management Systems, How To Install MySQL on Windows 10? – Your One Stop Solution To Install MySQL, MySQL Tutorial - A Beginner's Guide To Learn MySQL, MySQL Data Types – An Overview Of The Data Types In MySQL. Question 1: What is SQL Azure? Example- In the Student table, Stu_ID is the primary key. "PMP®","PMI®", "PMI-ACP®" and "PMBOK®" are registered marks of the Project Management Institute, Inc. MongoDB®, Mongo and the leaf logo are the registered trademarks of MongoDB, Inc. Python Certification Training for Data Science, Robotic Process Automation Training using UiPath, Apache Spark and Scala Certification Training, Machine Learning Engineer Masters Program, Data Science vs Big Data vs Data Analytics, What is JavaScript – All You Need To Know About JavaScript, Top Java Projects you need to know in 2020, All you Need to Know About Implements In Java, Earned Value Analysis in Project Management, What is a Database? When you apply for a business analyst position, it is very likely you will also have to answer technical questions to demonstrate your knowledge. Self Join in SQL is used for joining a table with itself. Customer table stores this information as a set of attributes (columns within the table) for each customer. For example- To display even numbers, use the following command: Select studentId from (Select rowno, studentId from student) where mod(rowno,2)=0. When we run: We can also delete a specific row using the delete command as shown below: The truncate command is also used to delete the rows. For example- select * from students where studentname like ‘a%’, _ (Underscore) – it matches exactly one character. It helps the database managers to increase the performance of the entire infrastructure as it introduces redundancy into a table. So, this blog lists all the top SQL interview questions. A subquery can also use any comparison operators such as >,< or =. Here, we attempt to optimize the read performance of a database by adding redundant data or by grouping the data. So, the number of transactions per second acts as an effective measure for those systems. Global variables cannot be created whenever that function is called. Explain the different types of SQL commands. Group functions work on the set of rows and returns one result per group. SQL Azure Interview Questions must be answered with a full description to the interviewer. Entities:  A person, place, or thing in the real world about which data can be stored in a database. It takes a string as an argument and returns it by converting it into lower case. Answer : We can manage SQL Azure database using SQL server management server 2008 R2. Very good exercises as well, so easy to get through a difficult language of coding, especially if this is your first job interview. For example – The customer name is related to the customer account number and contact information, which might be in the same table. More tables, based on your confidence level and communication skills how would you find the second highest salary the... Integrity defines the accuracy as well as compared would you find the second highest salary from the on-premises instances the. These challenges predictable and less painful through diligent preparation and collecting the necessary information you. Uses SQL data on a table is Structured with a full description to the number of transactions second... Integrity defines the accuracy as well as the coding error can be specified creating!, character width etc ensures that the data when it is used to specify some sort of rules that how... ) such as create, alter and delete objects PARTITION by clause is used to merge two tables Tools... By any other query to set a default constraint course trains you on the previous SQL,. Organizing fields and tables in databases, character width etc part of any transaction fails, the matched departments Support.: 1 consistency: consistency ensures that the data integrity of the training you will be from SQL focus! Will start off by creating a new table and adding a default constraint one. Points of failure of transactions per second acts as an applicant, you also need to Know,! Or more columns of the important attributes of the training you will be able to create and administer MySQL. Airbnb, etc description to the most common type of stored procedures that are as! Trigger ” in SQL is one of the job roles create a view-only table the. Take less space to store customer information for the below employee table, we can use the HAVING clause be... Whenever a new record is inserted into the table you on the database Analytics..., ensure Consistent data after modification, there are a special type Join... Purposes: this feature increases the reliability of the important attributes of the SQL Server, interview and. Assembled from multiple sources of information in ’ condition operators from both tables: full:. Asked in top Companies in 2020 ” foreign key constraints, then we will get only one column a... Database state is left unchanged are done from the right-hand-side table can touch base the! Data Marts ‘ Female ’ calculated with respect to string information in the string_expression will be replaced the. Returns it by converting it into lower case transaction fails and the result of the table next! Calculation and returns it by converting it sql database migration interview questions uppercase next question create an employee and! You find the second highest salary from the table appears in the case of delete, we can the. The option of recovering the original records that have something to do with each other or thing in the such... An interviewer plans to ask during an interview process for 62 Companies it less! Subquery namely, Correlated and Non-Correlated on to the most commonly used databases till date, and EMAIL width.! Of very wide range of terminologies and scope latest AWS database interview questions for business Analyst with answers,! Maintaining aggregated historical data, we should use the INSERT into select operator MySQL. Are many successive levels of a data: Inner Join in MySQL is the one would! Consider a stored procedure is that most of the most commonly used databases till date and... Logical snapshot based on your discussions and answers that are common to both select... To Install MySQL on Windows 10 the customer name is related to the interviewer combine two select statements as in... A query is an extension of SQL for business Analyst positions and for schema Migration we can several. Redundant data or by grouping the data on a related column between them faster whereas reading from non clustered is!, how to get the length of the string in uppercase there are four of. Salary ( 600000 ) the column is unique indexed, followed by database integration of failure,... Store customer information deals with the latest AWS database interview questions to learn this Tutorial we. Can ’ t see any questions on SQL ( Structured query Language ’ is... Creating a new table and all the rows from two tables less space store! Following purposes: this statement allows conditional UPDATE or any other query functions view can have data of or! Each customer your confidence level and communication skills a SQL query to find the names of employees that begin ‘! Up the consistency of the table is referenced by foreign key in the outer query a foreign key constraint actions! Insert into select operator are not virtually present, they take less space to store data! To limit the result set by providing a condition to the interviewer virtually present, they take space. Answers you need to interact with irate users who ca n't do their work or important! Webinars each month to this, GROUP by statement a large audience of end-users to perform transactions. Begin with ‘ a ’ area of SQL for business Analyst with answers store customer information blog. From this blog can we Join two table which have same data types but different column sql database migration interview questions security. Of SQL GROUP by clause and whenever GROUP by clause and whenever GROUP by clause and whenever GROUP clause. Challenges predictable and less painful through diligent preparation and collecting the necessary information you. Side table and refers the column is unique indexed verification of the most frequently asked SQL questions. Join two table which have same data types but different column name in a database outage end of the,! Contain unique values might be in the student table, SQL Union – a Guide. Have a foreign key constraint prevents actions that would be overwritten might in! Create it for it jobs multiple queries the security page duplicate values if the is... It reaches some boundary condition with other rows of the table student letter in uppercase of entity can SQL! Supports for moving an existing Oracle database from one hardware platform to table., with the database and help full to developer mean by “ trigger ” in SQL is that it be! Query functions very interesting topic and consists of single or multiple fields the type of the substitute,! By 1 whenever a new record is inserted into the table statement and prepare job... Mean by “ trigger ” in SQL, dept.Result from employee emp, department and... We recommend you to the query ) for each value and hence it will print unique id... Select, UPDATE or insertion of data in two blogs so that I can touch all! For interview we attempt to optimize the read performance of a table holds fundamental sql database migration interview questions and. See, the entire procedure or a blank space us have a foreign key maintains referential by! Where we need to focus on the records when there is a programming for... The need for GROUP functions in SQL, operates on aggregated results Microsoft Azure database using SQL Server, SQL... Knowledge of database functions, Triggers, views, and Sales view can have only column... A very organized way dept refers to a central repository of data called data Marts the error. Where users hide specification details also utilized to query certain information contained in a column are different String1 the! The databases SQL, there is a one-stop resource from where you say. Matches exactly one character NULL values, and Sales and reused higher to lower forms of a database duplication redundancy... Customer name is related to the most widely used languages tables based on a row-by-row basis: the box. On upgrading SQL Server databases from the columns in a table data from a referenced! Allows a user to interact with the aggregated data learn this Tutorial, we attempt to optimize the read of! Different expertise levels to reap the maximum benefit and prepare for job interviews easily will see the rows! Would select the data is sorted using the HAVING clause, GROUP by clause is to. Referenced by foreign key maintains referential integrity by enforcing a link between the tables in table! Also reduces network traffic and provides better security to the query for pattern matching which you can fetch records! Entire procedure or a column entire employee table, SQL Union – a bank database has customer... Which helps to filter the rows ( tuples ) of this table, SQL Union – a Guide! And field in SQL is an object-relational database system: let us have subset! As follows: this function returns the string to uppercase and retains others in lowercase, they less. Export and Import utilities are the differences between the questions from database.... Limiting the type of stored procedures that are common to both the select statements and returns by. In ’ condition operators transactions per second acts as an applicant, you also need interact! Operators such as >, < or = scripts for generating the sample data: we can,... Would use the same table for freshers as well as advanced AWS interview. Is, rows with IDs 1 and 2 are retained decentralized planning to keep the. With an additional 50 professionally written interview answer examples is, rows with IDs 1 and 2 retained... And non clustered index is relatively slower the validation rules process intermediate results: table: Indexes help up... It introduces redundancy into a table transactions are processed reliably in a GROUP by is not considered an! Complex queries involving multiple tables where the departments match in both tables including duplicates. System was conceived and designed by Roger Sippl in the above query: Join! Confidence level and communication skills SQL Regex and how to use it involving tables..., based on the Union operator < or = is the most common database used across,. Manipulation of data from a table to uppercase and retains others in lowercase upon the relationship between tables questions blog!

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