Quantified comparison predicate 

The quantified comparison predicate is used to compare a value with the result of a query.

Syntax

<quantified comparison predicate> ::=     <value expression> <comparison operator> ( ALL | SOME | ANY ) '(' <query specification> ')'.

 

The <query specification> must have the a result of one column. The data type of the <value expression> must be comparable to the type of that column.

If ALL is specified, the result of the <quantified comparison predicate> is:

• true, if the result of the <query specification> is empty or if the implied <comparison predicate> between the <value expression> and all the rows of the result of the <query specification> evaluates to true.
• false, if the implied <comparison predicate> between the <value expression> and at least one row of the result of the <query specification> evaluates to false.
• unknown, else.

If SOME or ANY is specified, the result of the <quantified comparison predicate> is:

• true, if the implied <comparison predicate> between the <value expression> and at least one row of the result of the <query specification> evaluates to true.
• false, if the result of the <query specification> is empty or if the implied <comparison predicate> between the <value expression> and all the rows of the result of the <query specification> evaluates to false.
• unknown, else.

Example

SELECT * FROM a WHERE c > ALL ( SELECT c FROM b )

The Quantified Comparison. This SELECT yields all rows from table a where the column a.c has a value that is greater than all values of column b.cin table b.

See

Value expressions, Query Specification