Question

我需要确定大量不同列中的重复项。我尝试使用以下代码，而不是键入每个列名称。这稍微有点效率，因为我只需要输入一次列名。但是，我收到了这个错误：

Msg 164，Level 15，State 1，Line 8 每个GROUP BY表达式必须包含至少一个不是外部引用的列。

declare @TheCount varchar(100)
set @TheCount = 'Column_1'
select @TheCount, count(@TheCount) as LineCount
from staging
group by @TheCount
having count(@TheCount) > 1
order by 2 desc

Answer 1

也许这个脚本很有用（假设是Sql Server）：

CREATE TABLE TEST(
a int
)

INSERT INTO TEST VALUES(1)
INSERT INTO TEST VALUES(1)
INSERT INTO TEST VALUES(2)
INSERT INTO TEST VALUES(3)
INSERT INTO TEST VALUES(4)
INSERT INTO TEST VALUES(4)

declare @TheCount varchar(100)
set @TheCount = 'a'

EXEC('select ' + @TheCount + ', count(' + @TheCount + ') as LineCount
      from test
      group by ' + @TheCount + '
      having count(' + @TheCount + ') > 1
      order by 2 desc')

您可以尝试此示例 here 。

注意：这是“动态Sql执行”的一个小例子，这里有link作为一点解释。

Answer 2

DECLARE @column_list varchar(4000) = 'column_name1,column_name2,column_name3,etc';

DECLARE @sql = '
  WITH dups AS (
    SELECT 
      *,ROW_NUMBER() OVER(PARTITION BY '+@column_list'+)) AS n
    FROM table_name
  SELECT * FROM dups WHERE n > 1';

EXEC @sql;

SQL - 将变量用作具有计数的列名（@variable）

2 个答案: