By specifying a quantified predicate (quantified_predicate), you can compare a value or list of values to a set of values or value lists.
Syntax
<quantified_predicate> ::= <expression> <comp_op> <quantifier> <expression_list>  <expression> <comp_op> <quantifier> <subquery>  <expression_list> <equal_or_not> <quantifier> (<expression_list>,...)  <expression_list> <equal_or_not> <quantifier> <subquery>
The following operators are available for comparing values:
Syntax
<comp_op> ::=
<
 >
 <>
 !=
 =
 <=
 >=
 ~= <! for computers with ASCII code !>
 ~< <! for computers with ASCII code !>
 ~> <! for computers with ASCII code !>
Only the following operators are available for comparing value lists:
Syntax
<equal_or_not> ::=
<>
 =
 ~= <! for computers with ASCII code !>
The quantified predicate can be qualified with ALL, SOME or ANY.
Syntax
<quantifier> ::=
ALL
 SOME
 ANY
SQL Tutorial, Subquery: Inner Queries
The subquery must supply a result table that contains the same number of columns as the number of values created by the expression (expression or expression_list) on the left of the operator.
Each list of values (expression_list) specified to the right of the equal_or_not comparison operator must contain the same number of values as specified in the value list in front of the equal_or_not operator.
Let x be the result of the first value expression and S the result of the subquery or sequence of values. S is a set of s values. The value x and the values in S must be comparable with each other.
If a value list (expression_list) is specified on the left of the comparison operator equal_or_not, then let x be the value list comprising the results of the values x1, x2, ..., xn of this value list. Let S be the result of the subquery consisting of a set of value lists s or a sequence of value lists s. A value list s consists of the results of the values s1, s2, ..., sn.
A value xm must be comparable with all values sm.
x=s is true if xm=sm, m=1,...,n
x<>s is true, if there is at least one m for which xm<>sm
x <equal_or_not> s is undefined, if there is no m for which xm <equal_or_not> sm is false, and if there is at least one m for which xm <equal_or_not> sm is undefined. If one xm or one sm is a NULL value, or if the result of the subquery is empty, then x <equal_or_not> y is undefined.
The entry '' in the list below means that no statement can be made if only the result of the comparison with one s is known.
x <compare> <quantifier> S, whereby <compare> ::= <comp_op>  <equal_or_not>

<quantifier> ::= ALL 
<quantifier> ::= ANY  SOME 

S is empty 
True 
False 
x <compare> S is true for at least one s from S 
 
True 
x <compare> S is true for all s from S 
True 
True 
x <compare> S is not false for any value s from S and is undefined for at least one value s 
Undefined 

S contains NULL values and x <compare> S is true for all other s 
Undefined 
True 
x <compare> S is false for at least one value s from S 
False 
 
x <compare> S is false for all s from S 
False 
False 
x <compare> S is not true for any value s from S and is undefined for at least one value s 
Undefined 

S contains NULL values and x <compare> S is true for all other s 
False 
Undefined 