SQL WHERE Clause

The WHERE Clause is used when you want to retrieve specific information from a table excluding other irrelevant data. For example, when you want to see the information about students in class 10th only then you do need the information about the students in other class. Retrieving information about all the students would increase the processing time for the query.

So SQL offers a feature called WHERE clause, which we can use to restrict the data that is retrieved. The condition you provide in the WHERE clause filters the rows retrieved from the table and gives you only those rows which you expected to see. WHERE clause can be used along with SELECT, DELETE, UPDATE statements.

Syntax of SQL WHERE Clause:

WHERE {column or expression} comparison-operator value

Syntax for a WHERE clause with Select statement is:

SELECT column_list FROM table-name 

WHERE condition;

·         column or expression - Is the column of a table or a expression

·         comparison-operator - operators like = < > etc.

·         value - Any user value or a column name for comparison