SQL 条件列存在性

Question

我是否可以以某种方式选择视图中存在的列，但如果不存在则忽略该列？

SELECT
    CASE
        WHEN EXISTS(SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'MyView' AND COLUMN_NAME = 'MyColumn')
            THEN MyView.MyColumn
        ELSE NULL
    END AS [Sometimes]
FROM
    MyView

现在，它会返回“Msg 207 无效的列名”错误。

也许可以选择忽略该错误？

Answer 1

您可以使用动态 SQL来做到这一点：

declare @sql varchar(200)   
IF EXISTS(SELECT 1 FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME = 'MyView' AND COLUMN_NAME = 'MyColumn') 
BEGIN
    select  @sql = "SELECT Column1 AS TheColumn1, MyColumn from MyView"
END
ELSE
BEGIN
    select  @sql = "SELECT Column1 AS TheColumn1, null AS MyColumn from MyView"
END 

-- executes dynamic sql
EXEC @sql