循环当前 table 以查找列是否为主键？

Question

我有一个名为#ColumnList 的临时文件 table，它包含一个列名列表。我需要遍历此 table 中的每一行并查看该列是否为主键。如果它是一个键，那么我需要将该列名添加到名为 PRIMARYKEYCOLUMN 的列中。

这是我目前所拥有的，但它不起作用。它抛出一个错误

Cannot insert the value NULL into column 'DataType', table 'tempdb.dbo.#ColumnList__________________0000000B0D8C'; column does not allow nulls. INSERT fails.

ALTER TABLE #ColumnList
ADD PRIMARYKEYCOLUMN VARCHAR(50);

INSERT INTO #ColumnList ([PRIMARYKEYCOLUMN])
(SELECT DISTINCT KU.column_name as PRIMARYKEYCOLUMN 
FROM 
sys.columns c 
       JOIN sys.types t ON t.user_type_id = c.user_type_id
                        AND t.system_type_id = c.system_type_id      
JOIN sys.tables tab ON c.object_id = tab.object_id
JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS TC ON TC.TABLE_NAME = tab.name 
INNER JOIN
    INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KU
          ON TC.CONSTRAINT_TYPE = 'PRIMARY KEY' AND
             TC.CONSTRAINT_NAME = KU.CONSTRAINT_NAME AND 
             KU.table_name='myTableName'    
JOIN #ColumnList cl ON cl.ColumnName = KU.COLUMN_NAME)

上面的子查询（没有 JOIN #ColumnList cl ON cl.ColumnName = KU.COLUMN_NAME）工作正常并且 returns 下面的结果。但是插入不起作用。

[PRIMARYKEYCOLUMN]
Column1
Column2
Column3

我需要将上面那些相同的列插入到存在这些相同列名的临时 table 中

Answer 1

更新语句可能有效，例如：

update
    #ColumnList  
set
    PRIMARYKEYCOLUMN = ColumnName 
where
    ColumnName in (
        SELECT
            DISTINCT KU.column_name  
        FROM
            sys.columns c         
        JOIN
            sys.types t 
                ON t.user_type_id = c.user_type_id                         
                AND t.system_type_id = c.system_type_id       
        JOIN
            sys.tables tab 
                ON c.object_id = tab.object_id 
        JOIN
            INFORMATION_SCHEMA.TABLE_CONSTRAINTS AS TC 
                ON TC.TABLE_NAME = tab.name  
        INNER JOIN
            INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KU           
                ON TC.CONSTRAINT_TYPE = 'PRIMARY KEY' 
                AND              TC.CONSTRAINT_NAME = KU.CONSTRAINT_NAME 
                AND               KU.table_name='myTableName'
        )

循环当前 table 以查找列是否为主键？

Loop through current table to find if column is a primary key?

sql

sql-server

ssms-2016