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Relational operators
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Table 49: Relational operators and resulting predicates
Relational
operator Predicate for this relational operator
= True if the two expressions are equal.
| != | ^=
Basic Predicate
A basic predicate compares two values using a relational operator. If a basic predicate specifies
a query expression, then the query expression must return a single value. Basic predicates often
specify an inner join.
If the value of any expression is null or the query_expression does not return any value, then the
result of the predicate is set to false. This is the syntax for a basic predicate:
Quantified Predicate
True if the two expressions are not equal. The operators != and ^= are
equivalent to .
< True if the first expression is less than the second expression.
True if the first expression is greater than the second expression.
>= True if the first expression is greater than or equal to the second
expression.
Syntax
expression relop { expression | ( query_expression ) }
The quantified predicate compares a value with a collection of values using a relational
operator. A quantified predicate has the same form as a basic predicate with the
query_expression being preceded by the ALL, ANY, or SOME keyword. The result table returned
by query_expression can contain only a single column.
When you specify ALL, the predicate evaluates to true if the query_expression returns no values
or the specified relationship is true for all the values returned.
When you specify SOME or ANY, the predicate evaluates to true if the specified relationship is true
for at least one value returned by the query_expression. There is no difference between the SOME
and ANY keywords. The predicate evaluates to false if the query_expression returns no values or
if the specified relationship is false for all the values returned. This is the syntax for a quantified
predicate:
Syntax
expression relop { ALL | ANY | SOME } ( query_expression )