x***n
发帖数: 39 | 1 Suppose the primary key you wanna set is MyTable.ColumnA
Then
SELECT MAX(Duplicates), ColumnA
FROM
( SELECT COUNT(*) AS Duplicates, ColumnA
FROM MyTable
GROUP BY ColumnA); | b*e
发帖数: 3845 | 2 maybe this would be better
select count(*) as dup, columnA from myTable group by ColumnA
having dup>1
【在 x***n 的大作中提到】
: Suppose the primary key you wanna set is MyTable.ColumnA
: Then
: SELECT MAX(Duplicates), ColumnA
: FROM
: ( SELECT COUNT(*) AS Duplicates, ColumnA
: FROM MyTable
: GROUP BY ColumnA);
| c**t
发帖数: 2744 | 3 Why need nested w-c?
select count(*), ColumnA
from TABLE
group by ColumnA
having count(*) > 1
【在 x***n 的大作中提到】
: Suppose the primary key you wanna set is MyTable.ColumnA
: Then
: SELECT MAX(Duplicates), ColumnA
: FROM
: ( SELECT COUNT(*) AS Duplicates, ColumnA
: FROM MyTable
: GROUP BY ColumnA);
|
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