Oracle ALL, ANY and SOME比较

ALL

The

ALL

comparison condition is used to compare a value to a list or subquery. It must be preceded by =, !=, >, <, <=, >= and followed by a list or subquery.

When the

ALL

condition is followed by a list, the optimizer expands the initial condition to all elements of the list and strings them together with

AND

operators

比较对象:一个值;一系列值或是子查询

位置:前 : =, !=, >, <, <=, >= ; 后 : 一系列值或子查询;

当比较对象是一系列值时,等价于 and连接这一系列值的分个比较;

SELECT empno, sal
FROM   emp
WHERE  sal > ALL (2000, 3000, 4000);

-- Transformed to equivalent statement without ALL.

SELECT empno, sal
FROM   emp
WHERE  sal > 2000 AND sal > 3000 AND sal > 4000;

当比较对象是子查询时,会先转译为any,然后转译为exists进行查询.并且子查询返回0行时,取比较结果为TRUE.

SELECT e1.empno, e1.sal
FROM   emp e1
WHERE  e1.sal > ALL (SELECT e2.sal
FROM   emp e2
WHERE  e2.deptno = 20);

-- Transformed to equivalent statement using ANY.

SELECT e1.empno, e1.sal
FROM   emp e1
WHERE  NOT (e1.sal <= ANY (SELECT e2.sal
FROM emp e2
WHERE e2.deptno = 20));

-- Transformed to equivalent statement without ANY.

SELECT e1.empno, e1.sal
FROM   emp e1
WHERE  NOT EXISTS (SELECT e2.sal
FROM emp e2
WHERE e2.deptno = 20
AND   e1.sal <= e2.sal);

ANY

The

ANY

comparison condition is used to compare a value to a list or subquery. It must be preceded by =, !=, >, <, <=, >= and followed by a list or subquery.

When the

ANY

condition is followed by a list, the optimizer expands the initial condition to all elements of the list and strings them together with

OR

operators.

比较对象:一个值;一系列值或是子查询

位置:前 : =, !=, >, <, <=, >= ; 后 : 一系列值或子查询;

当比较对象是一系列值时,等价于 or 连接这一系列值的分个比较;

SELECT empno, sal
FROM   emp
WHERE  sal > ANY (2000, 3000, 4000);

-- Transformed to equivalent statement without ANY.

SELECT empno, sal
FROM   emp
WHERE  sal > 2000 OR sal > 3000 OR sal > 4000;

当比较对象是子查询时,会转译为exists进行查询.并且子查询返回0行时,取比较结果为False.

SELECT e1.empno, e1.sal
FROM   emp e1
WHERE  e1.sal > ANY (SELECT e2.sal
FROM   emp e2
WHERE  e2.deptno = 10);

-- Transformed to equivalent statement without ANY.

SELECT e1.empno, e1.sal
FROM   emp e1
WHERE  EXISTS (SELECT e2.sal
FROM emp e2
WHERE e2.deptno = 10
AND   e1.sal > e2.sal);

SOME

The

SOME

and

ANY

comparison conditions do exactly the same thing and are completely interchangeable.

some
some和any是一致的,二者可以相互转化;