mysql 筛选重复项(单列或者多列同时重复)
SELECT检查字段,COUNT(检查字段)FROMtable_nameGROUP BY 检查字段HAVING COUNT(检查字段) > 1;//单列SELECT检查字段1, COUNT(检查字段1),检查字段2, COUNT(检查字段2),...FROMtable_nameGROUP BY...
·
SELECT
检查字段,
COUNT(检查字段)
FROM
table_name
GROUP BY 检查字段
HAVING COUNT(检查字段) > 1;//单列
SELECT
检查字段1, COUNT(检查字段1),
检查字段2, COUNT(检查字段2),
...
FROM
table_name
GROUP BY
检查字段1,
检查字段2, ...
HAVING
(COUNT(检查字段1) > 1) AND
(COUNT(检查字段2) > 1) AND
...
只有当列的组合重复时,行才被认为是重复的,所以在having子句中使用了and运算符,这点要注意哦。
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