What questions will you get in a SQL job interview?
When it comes to database management systems, especially Relational database management systems (RDBMS), SQL holds great significance. Since Relational database management systems are a widely used databases now days, a demand for SQL experts in the field of Database management is growing. In this blog I will acquaint you with some of the most commonly asked questions in an SQL interview.
Q1) Differentiate between SQL and MYSQL
SQL stands for Structured Query Language. It is a standard language.
It Is a Database management system.
SQL is an essential aspect of relational database, Which is used for managing and accessing a database.
IT is a relational database management system.
Q2) Explain table and field in excel
- A table represents a collection of data in an organized form of columns and rows. Field represents a number of columns In a table. For instance:
Table: Employee Information
Field: Std Id, Stu Name, Stu Marks
Q3) Differentiate between CHAR and VARCHAR2:
- Both Char and Varchar2 are used for datatypes of characters, however varchar2 is used for variable length character strings, while Char is used for fixed strings. For instance, char(10) would not be able to store a string that contains any other number of characters instead of 10, whereas varchar2(10) can store any length i.e 6,8,3 in this variable.
Q4) what is your understanding of data integrity?
- The accuracy and the consistency of the data stored in a database are specified by Data Integrity. It also determines integrity constraints when entering into an application or a database to impose business rules on the data.
Q5) State the query that is used to display current date?
- The built in function GetDate() is used to return the current timestamp/date.
Q6) What is your understanding of Index?
- In SQL an index pertains to a method of performance tuning to allow records form the table to be retrieved faster. For each value an index generates an entry and it will therefore be quicker to retrieve data.
Q7) Why do we need MERGE statement?
- This condition allows data to be modified conditionally or inserted into a table. It would perform an UPDATE if a row exists, or an INSERT if the row doesn’t exist.
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