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分享求一SQL语句
一张表中有字段A，B，C。如果字段A中有值相同，且对应B字段的值不同，则更新对应的字段C为某一值作为标记。不知道我说清楚了没有
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winingsky 2011-04-29
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对于每一条记录，记录字段A的值相同，并且字段B的值不相同，就更新该条记录中字段C的值（作为标记)
Freedom 2011-04-29
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[Quote=引用 2 楼 wjf8882300 的回复:]
假设表有一个唯一ID为id
UPDATE TB T
SET C = 1
WHERE
EXISTS
(
SELECT ID
FROM TB X
WHERE X.ID = T.ID
AND EXISTS
(
SELECT ID
FROM TB Y
WHERE Y.A = X.A
AND Y.B != X.B
AND ……
[/Quote]
++1
假设表有一个唯一ID为id
UPDATE TB T
SET C = 1
WHERE
EXISTS
(
SELECT ID
FROM TB X
WHERE X.ID = T.ID
AND EXISTS
(
SELECT ID
FROM TB Y
WHERE Y.A = X.A
AND Y.B != X.B
AND ……
[/Quote]
++1
direction917 2011-04-29
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[Quote=引用 2 楼 wjf8882300 的回复:]
假设表有一个唯一ID为id
UPDATE TB T
SET C = 1
WHERE
EXISTS
(
SELECT ID
FROM TB X
WHERE X.ID = T.ID
AND EXISTS
(
SELECT ID
……
[/Quote]
学习。
假设表有一个唯一ID为id
UPDATE TB T
SET C = 1
WHERE
EXISTS
(
SELECT ID
FROM TB X
WHERE X.ID = T.ID
AND EXISTS
(
SELECT ID
……
[/Quote]
学习。
wjf8882300 2011-04-29
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假设表有一个唯一ID为id
UPDATE TB T
SET C = 1
WHERE
EXISTS
(
SELECT ID
FROM TB X
WHERE X.ID = T.ID
AND EXISTS
(
SELECT ID
FROM TB Y
WHERE Y.A = X.A
AND Y.B != X.B
AND EXISTS
(
SELECT COUNT(ID),A
FROM TB Z
WHERE Z.A = X.A
GROUP BY A
HAVING COUNT(ID)>1
)
)
)
UPDATE TB T
SET C = 1
WHERE
EXISTS
(
SELECT ID
FROM TB X
WHERE X.ID = T.ID
AND EXISTS
(
SELECT ID
FROM TB Y
WHERE Y.A = X.A
AND Y.B != X.B
AND EXISTS
(
SELECT COUNT(ID),A
FROM TB Z
WHERE Z.A = X.A
GROUP BY A
HAVING COUNT(ID)>1
)
)
)
