动态 SQL 将执行结果存储在一个变量中，并将该结果连接起来形成一个完整的查询

Question

我正在尝试使用最终查询可以执行的动态列 name.So 进行查询

DECLARE @SQLFinal NVARCHAR(MAX)
DECLARE @SQLAlias NVARCHAR(MAX)='SELECT '',''+cast(ColumnName as varchar(20)) + '' as '' + cast(ColAliasName as varchar(20)) collate Latin1_General_CI_AS from #colandAlias' 
DECLARE @SQLAliasResult NVARCHAR(MAX)
EXEC sp_executesql @SQLAlias= @SQLAliasResult OUTPUT
select  @SQLAliasResult

--将sp_execute结果赋给一个变量，@SQLAliasResult.It给出NULL而不是exec结果

-- 目的是将上面的结果(@SQLAliasResult) 与belwo 查询部分连接起来形成一个完整的查询

set @SQLFinal='SELECT

ID,Name,custid '

+@SQLAliasResult+
' FROM dbo.tableCustomer where custid=71'

EXEC @SQLFinal

-- 如何将查询执行结果赋值到变量中执行@SQLFinal ?

---@SQLAliasResult

的输出

,col1 as [201911]
,col2 as [201912]
,col1 as [202001]
,col2 as [202002]

--@SQLFinal的内容

SELECT
ID,Name,custid 
,col1 as [201911]
,col2 as [201912]
,col1 as [202001]
,col2 as [202002]
FROM dbo.tableCustomer where custid=71

exec @SQLFinal 将从 dbo.tableCustomer 生成的别名

中给出所需的输出

Answer 1

我认为第2行不需要动态查询，我看不到动态字段。另外，我认为你需要这样的东西：

DECLARE @Columns TABLE(
    ColumnName SYSNAME
)

INSERT INTO @Columns VALUES ( 'Column1' ), ( 'Column2' );

DECLARE @SelectString   VARCHAR(255)

-- This is the sentence that is going to concat everything
SELECT  @SelectString = ISNULL( @SelectString + ', ', '' ) + ColumnName
    FROM @Columns;

-- Execute this or do what you need
SELECT @SelectString;

动态 SQL 将执行结果存储在一个变量中，并将该结果连接起来形成一个完整的查询

Dynamic SQL to store the execution result in a variable and concatenate that result to form a full query

sql

tsql

sql-server

dynamic-sql

sql-server-2012