sql server按数字选择列

问题描述

我可以通过 SQL 中的列数选择特定的列吗?类似的东西

Can I select specific columns by the number of the columns in SQL?Something like

SELECT columns(0), columns(3), columns(5), columns(8) FROM TABLE

谢谢

推荐答案

你必须使用动态 SQL 来做到这一点:

You have to use dynamic SQL to do this:

DECLARE @strSQL AS nvarchar(MAX)
DECLARE @strColumnName AS nvarchar(255)
DECLARE @iCounter AS integer
DECLARE @curColumns AS CURSOR


SET @iCounter = 0
SET @strSQL = N'SELECT '

SET @curColumns = CURSOR FOR
(
    SELECT * FROM
    (
        SELECT TOP 99999
            COLUMN_NAME
        FROM INFORMATION_SCHEMA.COLUMNS
        WHERE TABLE_NAME = 'T_Markers'
        AND ORDINAL_POSITION < 4
        ORDER BY ORDINAL_POSITION ASC
    ) AS tempT
)

OPEN @curColumns
FETCH NEXT FROM @curColumns INTO @strColumnName
WHILE @@FETCH_STATUS = 0
BEGIN
    -- PRINT @strColumnName
    IF @iCounter = 0
        SET @strSQL = @strSQL + N'
     [' + @strColumnName + N'] '
    ELSE
        SET @strSQL = @strSQL + N'
    ,[' + @strColumnName + N'] '
    SET @iCounter = @iCounter + 1
FETCH NEXT FROM @curColumns INTO @strColumnName
END
CLOSE @curColumns
DEALLOCATE @curColumns

SET @strSQL = @strSQL + N'
FROM T_Markers
'

PRINT @strSQL

这篇关于sql server按数字选择列的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！