[英]Use result of one query in another sql query
我有下面的表结构:
表格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 ║
╚════════╩═════════╝
我想写一个存储过程,它将根据Table1中的tableName和columnName列的值从Table1中选择数据,并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 ║ ║
╚═════╩═════╩════════╝
尝试临时表。 在这里看: http : //www.sqlteam.com/article/temporary-tables
您将需要一个动态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/
编辑:
以下代码可以解决问题。
我假设Table1
中的列Col1
是int类型。
我已使用Temp表生成所需的表。 您可以根据需要方便地将其替换成桌子。 我还使用了#table1
,可以将其替换为Table1
。
同样,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方法。
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
希望这可以帮助
已编辑答案以合并n行
码
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
结果
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
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