What is SQL and why tester need SQL?

What is SQL and why tester need SQL?

SQL stands for Structured Query Language. SQL is an ANSI (American National Standards Institute) standard computer language for accessing and manipulating database systems. SQL statements are used to retrieve and update data in a database. SQL works with database programs like MS Access, DB2, Informix, MS SQL Server, Oracle, Sybase, etc.

Why tester need SQL:

Yes, a tester needs to know SQL. When we do the back-end testing, we need to write SQL queries to retrieve the data from the database and compare this data to the one with reports or output.

Another scenario is, if something goes wrong in the application, for example, if there is an error, then we might have to write SQL queries to retrieve the data from the database and check what went wrong. Let’s say, we need to check in the Error Log table what went wrong. To check this, we query to the database, go to Error Log table and find out that happened. In the Error Log table, there are many records, so which one is your error then? To find out which one is yours, we need to write SQL queries. Example, you logged in to the application with User ID=devin99 and password=sn992jj. Now, to retrieve your record, you can write a query something like this: select * from Error_Log where userID=devin99; this query will retrieve your record only so that you can see what happened.