如何正确使用 "with" 命令

Question

我有一个查询并且有效，通过它我得到了类别子集。

with cte as (
    Select nid 
    from TB_Category 
    where nid = 429
    union ALL
    select ca.nid 
    from cte ct 
    inner join TB_Category ca on ca.parentid = ct.nid
)
SELECT p.nid 
from TB_Category p 
inner join cte ct on ct.nid = p.nid

要删除所选类别，我使用了以下命令，但出现错误：

DELETE FROM TB_Category 
WHERE nid in (
    with cte as (
        Select nid 
        from TB_Category 
        where nid = 429
        union ALL
        select ca.nid 
        from cte ct 
        inner join TB_Category ca on ca.parentid = ct.nid
    )
    SELECT p.nid 
    from TB_Category p 
    inner join cte ct on ct.nid = p.nid
)

显示以下错误：

Incorrect syntax near the keyword 'WHERE'.

Incorrect syntax near the keyword 'with'. If this statement is a common table expression, an xmlnamespaces clause or a change tracking context clause, the previous statement must be terminated with a semicolon.

Incorrect syntax near the keyword 'from'.

Incorrect syntax near the keyword 'with'.

Incorrect syntax near the keyword 'with'. If this statement is a common table expression, an xmlnamespaces clause or a change tracking context clause, the previous statement must be terminated with a semicolon.

Incorrect syntax near ')'.

Answer 1

在查询开始时使用 CTE，如下所示：

with cte as (
    Select nid 
    from TB_Category 
    where nid = 429
    union ALL
    select ca.nid 
    from cte ct 
    inner join TB_Category ca on ca.parentid = ct.nid
)    
DELETE
FROM TB_Category 
WHERE nid in (
    SELECT p.nid 
    from TB_Category p 
    inner join cte ct on ct.nid = p.nid
)

Answer 2

您可以使用连接删除：

WITH cte AS (
   SELECT nid 
   FROM TB_Category 
   WHERE nid= 429
   UNION ALL
   SELECT ca.nid 
   FROM cte ct 
   INNER JOIN TB_Category ca ON ca.parentid = ct.nid
)
DELETE t
FROM TB_Category t
INNER JOIN cte c ON c.nid = t.nid

但请注意，如果您在 nid 和 parentid 之间有一个真正的约束，删除将不会那么简单 - 如果删除尝试在子记录之前处理父记录，您可能会遇到约束冲突。

如何正确使用 "with" 命令

How can I use the "with" command correctly

sql

tsql

sql-server

common-table-expression