13.2.10.3 Subqueries with ANY, IN, or SOME
Syntax:
operand comparison_operator ANY (subquery)
operand IN (subquery)
operand comparison_operator SOME (subquery)
Where comparison_operator
is one of these operators:
= > < >= <= <> !=
The ANY
keyword, which must follow a comparison operator, means “return TRUE
if the comparison is TRUE
for ANY
of the values in the column that the subquery returns.” For example:
SELECT s1 FROM t1 WHERE s1 > ANY (SELECT s1 FROM t2);
Suppose that there is a row in table t1
containing (10)
. The expression is TRUE
if table t2
contains (21,14,7)
because there is a value 7
in t2
that is less than 10
. The expression is FALSE
if table t2
contains (20,10)
, or if table t2
is empty. The expression is unknown (that is, NULL
) if table t2
contains (NULL,NULL,NULL)
.
When used with a subquery, the word IN
is an alias for = ANY
. Thus, these two statements are the same:
SELECT s1 FROM t1 WHERE s1 = ANY (SELECT s1 FROM t2);
SELECT s1 FROM t1 WHERE s1 IN (SELECT s1 FROM t2);
IN
and = ANY
are not synonyms when used with an expression list. IN
can take an expression list, but = ANY
cannot. See Section 12.3.2, “Comparison Functions and Operators”.
NOT IN
is not an alias for <> ANY
, but for <> ALL
. See Section 13.2.10.4, “Subqueries with ALL”.
The word SOME
is an alias for ANY
. Thus, these two statements are the same:
SELECT s1 FROM t1 WHERE s1 <> ANY (SELECT s1 FROM t2);
SELECT s1 FROM t1 WHERE s1 <> SOME (SELECT s1 FROM t2);
Use of the word SOME
is rare, but this example shows why it might be useful. To most people, the English phrase “a is not equal to any b” means “there is no b which is equal to a,” but that is not what is meant by the SQL syntax. The syntax means “there is some b to which a is not equal.” Using <> SOME
instead helps ensure that everyone understands the true meaning of the query.