Quantified comparison predicate 
The quantified comparison predicate is used to compare a value with the result of a query.
Syntax
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
Syntax
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.c in table b.