Search conditions are used in the WHERE clause , HAVING clause and the ON conditions of the Joined Table . They are used to filter results of queries or to determine the evaluation of joins. Search conditions follow a three valued logic. The result of a search condition is true, false or unknown . A search condition is either a predicate or a complex Boolean expression of multiple search conditions.
<search condition> ::= <predicate> | <boolean expression>. <predicate> ::= <comparison predicate> | <quantified comparison predicate> | <between predicate> | <in predicate> | <like predicate> | <null predicate> | <exists predicate>.
Example
SELECT * FROM a WHERE NOT ( c < 1 ) AND c <= 100
This SELECT yields all rows from table a where the value of the column a.c not lower than 1 and lower or equal to 100 .