ria*_*iad 1 sql t-sql sql-server dynamic-sql
我有一个临时表:#temp321
select * from #temp321
它的回报价值就像
Field1|Field2|Field3|....|FieldN|
--------------------------------
Value1|Value2|Value3|....|ValueN|
这个#temp321表是从另一组查询中自动生成的.因此,#temp321表的列数可以变化(1-25).但他们将永远是一排.现在我需要使用这些值编写where语句.
示例:
where Field1='Value1' and Field2='Value2' and Field3='Value3'.....FieldN='ValueN'..(depends on number of column available into the #temp321 table)
我是如何做到的.提前致谢
你可以这样做:
SELECT *
FROM Othertable t1
INNER JOIN #temp321 t2 ON t1.Field1 = t2.field1
AND t1.Field2 = t2.field2
AND t1.Field3 = t2.field3;
更新:这是我能做的:
JOIN两个表动态而不是WHERE子句:DECLARE @DynamicJOINCondition AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);
;WITH cte
AS
(
SELECT t1.COLUMN_NAME 'T1', t2.COLUMN_NAME 'T2'
FROM
(
SELECT
ordinal_position ,
column_name
FROM information_schema.columns
WHERE table_name LIKE '#temp321%'
) t1
INNER JOIN
(
SELECT
ordinal_position ,
column_name
FROM information_schema.columns
WHERE table_name = 'othertable'
) t2 ON t1.ORDINAL_POSITION = t2.ORDINAL_POSITION
)
SELECT @DynamicJOINCondition = STUFF((SELECT distinct ' AND ' +
' t1.' + T1 + ' = ' + 't2.' + T2
FROM cte
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)'), 4,1,'');
-- Remove the first AND
SELECT @DynamicJOINCondition = RIGHT(@DynamicJOINCondition,
LEN(@DynamicJOINCondition) - 4);
SET @query = 'SELECT COUNT(*) ' +
' FROM #temp321 t1 INNER JOIN Othertable t2 ON ' +
@DynamicJOINCondition;
EXECUTE(@query);
这是怎么回事？
首先,我JOIN通过从临时表中获取列名列表以及从另一个表中获取列名的其他列表来动态生成条件.请注意它.我使用了列的列ORDINAL_POSITION,它是存储在information_schema.columns数据库中每列的表中的元数据,用于比较两个表中的列名列表.对于exapmle,带有adjcary postition 1的列将与列名称连接,而第二个表中的普通位置1也是如此.因此,您必须注意临时表列的位置,以便列出的列与第二个表的其他列列表的顺序相同.
UPDATE2:
WHERE动态生成子句:如果要WHERE动态生成子句而不是使用JOIN,在这种情况下需要更多的工作.像这样:
DECLARE @DynamicWHERECondition AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);
;WITH cte
AS
(
SELECT t1.COLUMN_NAME 'T1', t2.COLUMN_NAME 'T2'
FROM
(
SELECT
ordinal_position,
column_name
FROM information_schema.columns
WHERE table_name LIKE '#temp321%'
) t1
INNER JOIN
(
SELECT
ordinal_position,
column_name
FROM information_schema.columns
WHERE table_name = 'othertable'
) t2 ON t1.ORDINAL_POSITION = t2.ORDINAL_POSITION
), cte2
AS
(
SELECT t2, fieldvalue
FROM cte t1
INNER JOIN
(
SELECT FieldName, fieldvalue
FROM
(
SELECT field1, field2, field3, field4
FROM #temp321
) p
UNPIVOT
(
fieldvalue FOR FieldName IN (field1, field2, field3, field4)
) AS u
) t2 ON t1.T2 = t2.FieldName
)
SELECT @DynamicWHERECondition = STUFF((SELECT distinct ' AND ' +
T2 + ' = ' + '''' + fieldvalue + ''''
FROM cte2
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)'), 4,1,'');
SELECT @DynamicWHERECondition = RIGHT(@DynamicWHERECondition, LEN(@DynamicWHERECondition) - 4);
SET @query = 'SELECT COUNT(*) ' +
' FROM Othertable t2 WHERE ' + @DynamicWHERECondition;
EXECUTE(@query);
这是怎么回事？
由于临时表只包含一行,其中的值将用于形成动态创建的WHERE子句,因此我UNPIVOT将这一行编辑为两列:fieldname: field1, field2, ...和fieldvalue: value1, value2, ....
后来我加入了这个不透明的列,其中包含了我在第一个查询中使用的两个表:
SELECT
ordinal_position,
column_name
FROM information_schema.columns
WHERE table_name LIKE '#temp321%';
和:
SELECT
ordinal_position,
column_name
FROM information_schema.columns
WHERE table_name = 'othertable';
连接条件与第一种情况下的条件相同,即两个表中列的顺序位置.
WHERE动态生成子句,动态生成UNPIVOT临时表的值:但是之前的方法存在很大问题.选择你需要动态地移动表temp,如下所示:
SELECT @cols = STUFF((SELECT DISTINCT ',' + QUOTENAME(column_name)
FROM information_schema.columns
WHERE table_name LIKE '#temp321%'
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)'), 1, 1, '');
SET @dynamicunpivotquery = ' SELECT FieldName, fieldvalue ' +
' FROM ' +
' ( SELECT * FROM #temp321 ' +
' ) p ' +
' UNPIVOT ' +
' ( ' +
' fieldvalue FOR FieldName IN (' + @cols + ' ) ' +
' ) AS u ';
但是,为了在我们的查询中稍后使用动态不透明的表,您必须创建临时表:
DECLARE @unpivotedTable TABLE(FieldName varchar(50), fieldvalue VARCHAR(50));
INSERT INTO @unpivotedTable
exec(@dynamicunpivotquery);
所以你可以像这样使用它:
SELECT t2, fieldvalue
FROM cte t1
INNER JOIN @unpivotedTable t2 ON t1.T2 = t2.FieldName
这是带动态unpivot的更新的sql:
DECLARE @DynamicWHERECondition AS NVARCHAR(MAX);
DECLARE @cols AS NVARCHAR(MAX);
DECLARE @dynamicunpivotquery AS NVARCHAR(MAX);
DECLARE @query AS NVARCHAR(MAX);
DECLARE @unpivotedTable TABLE(FieldName varchar(50), fieldvalue VARCHAR(50));
SELECT @cols = STUFF((SELECT DISTINCT ',' + QUOTENAME(column_name)
FROM information_schema.columns
WHERE table_name LIKE '#temp321%'
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)'), 1, 1, '');
SET @dynamicunpivotquery = ' SELECT FieldName, fieldvalue ' +
' FROM ' +
' ( SELECT * FROM #temp321 ' +
' ) p ' +
' UNPIVOT ' +
' ( ' +
' fieldvalue FOR FieldName IN (' + @cols + ' ) ' +
' ) AS u ';
INSERT INTO @unpivotedTable
exec(@dynamicunpivotquery);
;WITH cte
AS
(
SELECT t1.COLUMN_NAME 'T1', t2.COLUMN_NAME 'T2'
FROM
(
SELECT
ordinal_position,
column_name
FROM information_schema.columns
WHERE table_name LIKE '#temp321%'
) t1
INNER JOIN
(
SELECT
ordinal_position,
column_name
FROM information_schema.columns
WHERE table_name = 'othertable'
) t2 ON t1.ORDINAL_POSITION = t2.ORDINAL_POSITION
), cte2
AS
(
SELECT t2, fieldvalue
FROM cte t1
INNER JOIN @unpivotedTable t2 ON t1.T2 = t2.FieldName
)
SELECT @DynamicWHERECondition = STUFF((SELECT distinct ' AND ' +
T2 + ' = ' + '''' + fieldvalue + ''''
FROM cte2
FOR XML PATH(''), TYPE
).value('.', 'NVARCHAR(MAX)'), 4,1,'');
SELECT @DynamicWHERECondition = RIGHT(@DynamicWHERECondition,
LEN(@DynamicWHERECondition) - 4);
SET @query = 'SELECT COUNT(*) ' +
' FROM Othertable t2 WHERE ' + @DynamicWHERECondition;
EXECUTE(@query);