问题描述

我有同一个数据库的两个实例.第一个 db 代表今天的数据，第二个数据来自 6 个月前.我需要找到特定表中条目子集的差异.

I have two instances of the same database. The first db represents data from today, the second data from 6 months ago. I need to find differences for a subset of entries in a specific table.

对于两个表中都有 id 的条目，我想找到一种方法来仅查看不相同的行.

For entries with ids that are in both tables, I'd like to find a way to view only the rows that aren't identical.

有什么想法吗?

谢谢

推荐答案

SELECT t1.id
FROM table1 t1
INNER JOIN table2 t2 ON t1.id = t2.id
WHERE ISNULL(t1.field1,'') <> ISNULL(t2.field1,'')
      OR ISNULL(t1.field2,'') <> ISNULL(t2.field2,'')
      OR ...

要生成长的 WHERE 部分，您可以使用此功能:

To produce long WHERE part you can use this function:

CREATE PROCEDURE compareTables
    @db1    NVARCHAR(100),
    @table1 NVARCHAR(100),
    @db2    NVARCHAR(100),
    @table2 NVARCHAR(100)
AS
BEGIN
    SET NOCOUNT ON;
    DECLARE @where NVARCHAR(MAX)
    DECLARE @cmd NVARCHAR(MAX)

    SET @where = ''

    SELECT @where = @where + 'ISNULL(t1.' + name + ','''') <> ISNULL(t2.' + name + ','''') OR ' 
    FROM sys.columns WHERE object_id = OBJECT_ID(@table1)

    SET @where = SUBSTRING(@where,1,LEN(@where)-3)

    SET @cmd = 'SELECT t1.id FROM ' + @db1 + '.' + @table1 + ' t1 '
    SET @cmd = @cmd + 'INNER JOIN ' + @db2 + '.' + @table2 + ' t2 ON t1.id = t2.id '
    SET @cmd = @cmd + 'WHERE ' + @where

    EXEC sp_executesql @cmd
END
GO

示例用法:

EXEC compareTables 'db1_name','dbo.table1','db2_name','dbo.table1'

记得把schema放在表名中.

Remember to put schema in the table name.

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