在另一个sql查询中使用一个查询的结果

时间:2014-03-12 06:07:53

标签: sql sql-server stored-procedures dynamic-sql

我有以下表结构:

表1

╔═════╦══════╦═════════════╦═════════════╗
║Col1 ║ Col2 ║ TableName   ║ ColumnName  ║
╠═════╬══════╬═════════════╬═════════════╣
║  1  ║ abc  ║ Table2      ║ column2     ║
║  2  ║ xyz  ║             ║             ║
║  3  ║ pqr  ║ Table1      ║ column1     ║
║  4  ║ jbn  ║             ║             ║
╚═════╩════════════════════╩═════════════╝

Table2 :   

 ╔════════╦═════════╗
 ║Column1 ║ Column2 ║
 ╠════════╬═════════╣
 ║  1     ║ A       ║
 ║  2     ║ B       ║
 ║  3     ║ C       ║
 ║  4     ║ D       ║
 ╚════════╩═════════╝

Table3

╔════════╦═════════╗
║Column1 ║ Column2 ║
╠════════╬═════════╣
║  1     ║ X       ║
║  2     ║ Y       ║
║  3     ║ Z       ║
║  4     ║ A       ║
╚════════╩═════════╝

我想编写存储过程,它将根据Table1中列tableName和columnName的值从Table1中选择数据和从另一个表中选择数据。

我想要以下格式的数据:

╔═════╦═════╦════════╗
║Col1 ║ Col2║ List   ║
╠═════╬═════╬════════╣
║  1  ║ abc ║A,B,C,D ║
║  2  ║ xyz ║        ║
║  3  ║ pqr ║1,2,3,4 ║
║  4  ║ jbn ║        ║
╚═════╩═════╩════════╝

3 个答案:

答案 0 :(得分:1)

尝试临时表。 看看这里:http://www.sqlteam.com/article/temporary-tables

答案 1 :(得分:0)

你需要一个动态的sql来获得这样的选择。查看链接http://www.mssqltips.com/sqlservertip/1160/execute-dynamic-sql-commands-in-sql-server/

修改

以下代码可以解决问题。

我假设Col1中的Table1列是int类型。

我使用Temp表生成所需的表。您可以根据自己的方便将其替换为您的桌子。我还使用了#table1,您可以将其替换为Table1

此外,这在性能方面可能不是很好,但这是我现在能想到的最好的。

declare @count int, @Query VARCHAR(5000), @counter int, @tableName VARCHAR(50), @ColumnName VARCHAR(50), @Col1 INT, @Col2 VARCHAR(50)
select @count = count(0) from #table1
SET @counter = 1

CREATE TABLE #table4
(
    Col1 INT,
    Col2 VARCHAR(50),
    List VARCHAR(50)
)

WHILE @counter <= @count
BEGIN
    SELECT @tableName = TableName, @ColumnName = columnName, @Col1 = Col1, @Col2 = Col2 FROM #Table1 WHERE Col1 = @counter

    SELECT @Query = 'INSERT INTO #table4 (Col1 , Col2) VALUES (' + CONVERT(varchar(50),@Col1) + ', ''' + @Col2 + ''')'
    EXEC (@Query)
    SELECT @Query = ''

    IF ISNULL(@tableName, '') != '' AND ISNULL(@ColumnName, '') != ''
    BEGIN
        SELECT @Query = 'UPDATE #table4 SET LIST = STUFF((SELECT '','' + CONVERT(VARCHAR(50), ' + @ColumnName + ') FROM ' + @tableName + ' FOR XML PATH('''')),1,1,'''') WHERE Col1 = ' + CONVERT(varchar(50),@Col1)

        EXEC (@Query)
    END
    SET @counter = @counter + 1
END

SELECT * FROM #table4

希望这有帮助

答案 2 :(得分:0)

为了合并n个行而编辑的答案

CODE

 drop table #temp1
declare @tabletemp as varchar (10)
declare @columntemp as varchar (10)
Declare @sqlTemp NVARCHAR(400)
declare @counter1 as int
declare @counter2 as int
select @counter2 = 1

select name,cname into #temp1 from test1
select @counter1 = COUNT(*) from #temp1


while (@counter2<= @counter1)
begin
SET @tabletemp = (SELECT MIN(name) FROM #temp1)
select @columntemp = (select min(cname) from #temp1 where #temp1.name = @tabletemp)

set @sqlTemp='select '+@columntemp +'  from '+@tabletemp
exec(@sqlTemp)

delete from #temp1 where name = @tabletemp and cname = @columntemp

select @counter1 = COUNT(*) from #temp1
end

RESULT

select * from test1 
name    cname
table1  column1
test2   colname
table1  test
test2   name

select column1 from table1
column1
qwer
asdff
zxcvb
qwer
asdff
zxcvb

select colname from test2
colname
testing
wer
ewrth
sfsf
testing
wer
ewrth
sfsf

select test from table1
--got error message inavlid column nae 'test' as this column does not exist

select name from test2 
name
table1
table1
table3
table2
table1
table1
table3
table2