Where Clause
The Where clause specifies the conditions that rows must meet to be retrieved. The Where clause contains conditions in the form:
WHERE expr1rel_operatorexpr2
expr1 and expr2 can be field names, constant values, or expressions.
rel_operator is the relational operator that links the two expressions. See
SQL Expressions for details.
For example, the following Select statement retrieves the names of employees that make at least $20,000.
SELECT last_name,first_name FROM emp WHERE salary >= 20000
