Question

有没有办法在不创建表的情况下在SQL Server中循环遍历多个数据库？我必须创建一个表才能运行下面的查询。我想在不创建表的情况下运行此查询，并在一个网格中显示结果。我尝试用{替换insert into WSA.dbo.TEST但是错误。还有另一种循环方式，不需要我创建一个表格并在一个网格上显示我的所有结果吗？

Answer 1

好吧，我没有看到您实际返回或显示任何结果的任何地方，但这是一种更简单的方法来完成您的代码当前正在做的事情（您可以填写...详细信息）：

DECLARE @x TABLE(db SYSNAME);

INSERT @x VALUES('Hs'),('Ge'),('At'),('LW'),('SE'),('LL');

DECLARE @sql NVARCHAR(MAX) = N'';

SELECT @sql += N'INSERT WSA.dbo.TEST(column list please)
  SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ...
    FROM ' + db + '_Active.dbo.DTLPAYMENTS AS d) sq
    GROUP BY ptno, cd, rn;
' FROM @x;

PRINT @sql;
-- EXEC sp_executesql @sql;

然而，重新阅读后，你必须将最后的SELECT从代码中删除 - 我认为重点是插入表中，而不是仅仅在单个网格中显示结果。如果你想避开桌子，那么你可以说：

DECLARE @x TABLE(db SYSNAME);

INSERT @x VALUES('Hs'),('Ge'),('At'),('LW'),('SE'),('LL');

DECLARE @sql NVARCHAR(MAX) = N'';

SELECT @sql += N'UNION ALL
  SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ...
    FROM ' + db + '_Active.dbo.DTLPAYMENTS AS d) sq
    GROUP BY ptno, cd, rn
' FROM @x;

SET @sql = STUFF(@sql, 1, 11, '');

PRINT @sql;
-- EXEC sp_executesql @sql;

此查询的输出（如this SQLfiddle中所示）如下：

SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ... 
FROM Hs_Active.dbo.DTLPAYMENTS AS d) sq 
GROUP BY ptno, cd, rn 
UNION ALL 
SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ... 
FROM Ge_Active.dbo.DTLPAYMENTS AS d) sq 
GROUP BY ptno, cd, rn 
UNION ALL 
SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ... 
FROM At_Active.dbo.DTLPAYMENTS AS d) sq 
GROUP BY ptno, cd, rn 
UNION ALL 
SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ... 
FROM LW_Active.dbo.DTLPAYMENTS AS d) sq 
GROUP BY ptno, cd, rn 
UNION ALL 
SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ... 
FROM SE_Active.dbo.DTLPAYMENTS AS d) sq 
GROUP BY ptno, cd, rn 
UNION ALL 
SELECT ptno, MAX ... FROM (SELECT d.*, row_number() ... 
FROM LL_Active.dbo.DTLPAYMENTS AS d) sq 
GROUP BY ptno, cd, rn

当您填写...部分时，应在所有6个数据库中生成有效的UNION ALL查询。如果你没有在PRINT输出中得到它，那么我怀疑你将查询转录错误或者你将无效的东西放入......部分。

STUFF()函数只是在执行之前删除第一个UNION ALL子句。

当然，您不会在此结果中知道哪些行来自哪个数据库。如果需要，可以添加：

SELECT @sql += N'UNION ALL
  SELECT ''' + db + ''', ptno, MAX ... FROM (SELECT d.*, row_number() ...
    FROM ' + db + '_Active.dbo.DTLPAYMENTS AS d) sq
    GROUP BY ptno, cd, rn;
' FROM @x;

Answer 2

为了尽可能少地修改代码逻辑，我将采取以下措施来避免使用永久表...

USE     WSA
Delete  From TEST
GO
DECLARE @Database varchar(20), 
        @i int = 0,
        @SQL Nvarchar(2000)

Declare @table Table 
       (ptno Int, --Or whatever datatype it should be
        dr_cd Int, --Or whatever datatype it should be
        dr_amt Int, --Or whatever datatype it should be
        dr_desc Int, --Or whatever datatype it should be
        cr_cd Int, --Or whatever datatype it should be
        cr_amt Int, --Or whatever datatype it should be
        cr_desc Int) --Or whatever datatype it should be


WHILE   @i < 6     
BEGIN     
        if @i = 0 SELECT @Database = 'Hs_Active'     
        if @i = 1 SELECT @Database = 'Ge_Active'       
        if @i = 2 SELECT @Database = 'At_Active'   
        if @i = 3 SELECT @Database = 'LW_Active'     
        if @i = 4 SELECT @Database = 'SE_Active'     
        if @i = 5 SELECT @Database = 'LL_Active'     

        Set     @SQL = 'USE '+@Database +'       
                         insert into WSA.dbo.TEST      
                        Select ptno,
                           max(case sign(amt) when 1 then cd end) dr_cd,
                           max(case sign(amt) when 1 then amt end) dr_amt,
                           max(case sign(amt) when 1 then description end) dr_desc,
                           max(case sign(amt) when -1 then cd end) cr_cd,
                           max(case sign(amt) when -1 then amt end) cr_amt,
                           max(case sign(amt) when -1 then description end) cr_desc
                         from (select d.*, 
                                     row_number() over (partition by ptno, cd, sign(amt) 
                                                    order by abs(amt)) rn
                             from DTLPAYMENTS d) sq
                        group by ptno, cd, rn'

        Insert  @table
        Exec    sp_executeSQL @SQL

        SELECT @i=@i+1      
END

--      Whatever you want to do with @table aka results

SQL循环显示结果

2 个答案: