子查询在 SQL SErver 2008 中返回了超过 1 个值

Question

请看我之前的问题，我仍然坚持。

我有 4 列需要处理，我不能删除 table 来将第 4 列从 int not null 更改为

我是从这个原始陈述中被引导的：

INSERT into ADVNET.dbo.KenCatItemTest
(categoryitemid,itemid,categoryid)
SELECT NEWID(),itemid,'0FCA508F-7EB5-4C2E-8803-DE688C4126E5'
FROM janel.dbo.item
WHERE janel.dbo.item.itemnumber like 'c-%' and listprice > 0

并抛出错误：

无法将值 NULL 插入列 'LineSequence'、table 'ADVNET.dbo.KenCatItemTest'；列不允许空值。插入失败。声明已终止。

所以现在我正在看这个声明：

DECLARE @CategoryItemId uniqueidentifier;  
SET @CategoryItemId = NEWID();  
DECLARE @ItemID uniqueidentifier;  
SET @ItemId = (select itemid from janel.dbo.item
WHERE janel.dbo.item.itemnumber like 'c-%' and listprice > 0 );
DECLARE @CategoryID uniqueidentifier;
SET @CategoryID = '0FCA508F-7EB5-4C2E-8803-DE688C4126E5';
DECLARE @LineSequence int;
SELECT @LineSequence = ISNULL(MAX(LineSequence),0) + 1  
FROM KenCatItemTest WHERE CategoryId = @CategoryId;
INSERT INTO ADVNET.dbo.KenCatItemTest
(CategoryItemId, ItemId, CategoryId, LineSequence)
VALUES (@CategoryItemId, @ItemId, @CategoryId, @LineSequence)

这个新语句抛出错误：

Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression. Msg 515, Level 16, State 2, Line 5 Cannot insert the value NULL into column 'ItemId', table 'ADVNET.dbo.KenCatItemTest'; column does not allow nulls. INSERT fails. The statement has been terminated.

Answer 1

此语句导致问题：

SET @ItemId = (select itemid from janel.dbo.item
WHERE janel.dbo.item.itemnumber like 'c-%' and listprice > 0 );

如果满足条件的行不止一行，则会发生错误，因为 SET 语句期望在右侧返回标量值而不是行集。

要解决此问题，您可以将标准缩小到只返回一行的位置，或者执行类似提取第一个值的操作。

例如：

SET @ItemId = (select TOP 1 itemid from janel.dbo.item
WHERE janel.dbo.item.itemnumber like 'c-%' and listprice > 0 );

Answer 2

你不能只使用 Row_number() 来为 LineSequence 生成一个值吗？

    INSERT INTO ADVNET.dbo.KenCatItemTest(
           categoryitemid
          ,itemid
          ,categoryid
          ,LineSequence)
    SELECT 
           NEWID()
          ,itemid
          ,'0FCA508F-7EB5-4C2E-8803-DE688C4126E5'
          ,ROW_NUMBER() OVER(ORDER BY ItemId)
      FROM 
           janel.dbo.item i
     WHERE 
           i.itemnumber LIKE 'c-%' 
       AND listprice > 0

子查询在 SQL SErver 2008 中返回了超过 1 个值

Subquery returned more than 1 value in SQL SErver 2008

sql

tsql

sql-server

sql-server-2008

scalar-subquery