Where (SQL) - Overview

Overview

WHERE is an SQL reserved word.

The WHERE clause is used in conjunction with SQL DML statements, and takes the following general form:

SQL-DML-Statement FROM TABLE_NAME WHERE predicate

all rows for which the predicate in the WHERE clause is True are affected (or returned) by the SQL DML statement or query. Rows for which the predicate evaluates to False or Unknown (NULL) are unaffected by the DML statement or query.

The following query returns only those rows from table mytable where the value in column mycol is greater than 100.

SELECT * FROM mytable WHERE mycol > 100

The following DELETE statement removes only those rows from table mytable where the column mycol is either NULL or has a value that is equal to 100.

DELETE FROM mytable WHERE mycol IS NULL OR mycol = 100