sql server实现copy data功能的存储过程（公共代码）

 1 CREATE PROCEDURE proc_update          //需要传入目标表的名字
 2     @target_table_name varchar(200)
 3 AS
 4 BEGIN
 5 
 6     DECLARE @primary_key_name varchar(50) //表主键的名字
 7     DECLARE @source_table_name varchar(220) //源表的名字
 8     DECLARE @upsert_sql nvarchar(max)    //sql字符串
 9 
10     SET @source_table_name = ‘shadow_‘ + @target_table_name //源表的名字由目标表名拼写出来
11     SET @primary_key_name = (
12         SELECT COLUMN_NAME
13         FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
14         WHERE TABLE_NAME = @target_table_name
15     )                                                 //获取主键名字
16 
17     DECLARE @column_name_str nvarchar(max)
18     DECLARE @column_name_str_values nvarchar(max)
19     DECLARE @column_name_without_pri_key_str nvarchar(max)
20 　　//获取目标表列名集合并用逗号分隔。比如(id,name,age)
21     SELECT @column_name_str = name FROM (
22         SELECT stuff(
23             (
24                 SELECT ‘,‘ + name
25                 FROM sys.columns
26                 WHERE object_id = object_id(@target_table_name)
27                 for xml path(‘‘)
28             ), 1, 1, ‘‘) as name
29     ) as n
30 　　//获取源表的列集合并用逗号（，）分隔。比如（S.id,S.name,S.age）
31     SELECT @column_name_str_values = name FROM (
32         SELECT stuff(
33             (
34                 SELECT ‘,S.‘ + name
35                 FROM sys.columns
36                 WHERE object_id = object_id(@target_table_name)
37                 for xml path(‘‘)
38             ), 1, 1, ‘‘) as name
39     ) as n
40 　　//更新的时候不需要更新主键，获取update set 语句的字符串拼接（比如 T.name = S.name, T.age = S.age）
41     SELECT @column_name_without_pri_key_str = name FROM (
42         SELECT stuff(
43             (
44                 SELECT ‘,T.‘ + name + ‘=‘ + ‘S.‘ + name
45                 FROM sys.columns
46                 WHERE object_id = object_id(@target_table_name) and columns.name <> @primary_key_name
47                 for xml path(‘‘)
48             ), 1, 1, ‘‘) as name
49         ) as n
50 　　 // 这里是主要逻辑 用到了merge方法（自行查阅用法）
51     SET @upsert_sql = ‘ MERGE INTO ‘ + @target_table_name + ‘ AS T‘ +
52                       ‘ USING (SELECT * FROM ‘ + @source_table_name + ‘ ) AS S‘ +
53                       ‘ ON T.‘+ @primary_key_name + ‘ = S.‘ + @primary_key_name +
54                       ‘ WHEN MATCHED THEN‘ +
55                       ‘ UPDATE SET ‘ + @column_name_without_pri_key_str +
56                       ‘ WHEN NOT MATCHED THEN‘ +
57                       ‘ INSERT (‘ + @column_name_str + ‘)‘ +
58                       ‘ VALUES (‘ + @column_name_str_values + ‘);‘ +
59                       ‘ TRUNCATE TABLE ‘ + @source_table_name + ‘;‘
60     exec(@upsert_sql)
61 
62 END
63 go