Recursive CTE Error: Types do not match

Question

我有这个 CTE

WITH items AS ( 
        SELECT 1 AS lvl, 
               i.[No_] [Parent Item No_], 
               i.[No_], 
               i.[Description], 
               CAST(N'' AS NVARCHAR(20)) /* COLLATE Latin1_General_100_CS_AS  */ 
        FROM Item i
        LEFT JOIN KitComponent bc ON bc.[Parent Item No_] = i.[No_] 
        LEFT JOIN Item ci ON ci.[No_] = bc.[No_] 
        GROUP BY i.[No_], i.[Description], i.[Unit Price] 

        UNION ALL

        SELECT i.lvl + 1, 
               i.[No_], 
               i2.[No_], 
               i2.[Description], 
               CAST(bc.[Variant Code] AS NVARCHAR(20)) 
        FROM KitComponent bc
        JOIN items i ON i.[No_] = bc.[Parent Item No_]
        JOIN Item i2 ON i2.[No_] = bc.[No_] 
) 
SELECT * FROM items WHERE [Parent Item No_] = '4000540001'

它在一台服务器上工作，没有指定排序规则的注释部分。然后我将整个东西复制到另一个 window，其中同一数据库的复制副本位于另一台服务器上并出现此错误。

Types don't match between the anchor and the recursive part in column "Variant Code" of recursive query "items".

我最初也没有那些 CAST 功能，它在服务器 #1 上工作得很好。最后，我将 collate 命令放在 CTE 的顶部，然后它在两台机器上都可以使用。

我通过SELECT @@VERSION

查看版本

Microsoft SQL Server 2012 (SP3) (KB3072779) - 11.0.6020.0 (X64) 
  Oct 20 2015 15:36:27 
  Copyright (c) Microsoft Corporation
  Standard Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1)
  (Hypervisor)

Microsoft SQL Server 2012 (SP3) (KB3072779) - 11.0.6020.0 (X64) 
  Oct 20 2015 15:36:27 
  Copyright (c) Microsoft Corporation
  Standard Edition (64-bit) on Windows NT 6.1 <X64> (Build 7601: Service Pack 1)
  (Hypervisor)

而且它们是相同的，所以我认为这一定是一些不同的选项设置。

有谁知道我在哪里查看那个选项？

Answer 1

来自 WITH 文档：

The data type of a column in the recursive member must be the same as the data type of the corresponding column in the anchor member.

因此它应该具有相同的数据类型、长度、排序规则......

在你的例子中：

WITH items AS ( 
        SELECT 1 AS lvl, 
               i.[No_] [Parent Item No_], 
               i.[No_], 
               i.[Description], 
               CAST(N'' AS NVARCHAR(20)) -- default DB collation
        FROM Item i
        LEFT JOIN KitComponent bc ON bc.[Parent Item No_] = i.[No_] 
        LEFT JOIN Item ci ON ci.[No_] = bc.[No_] 
        GROUP BY i.[No_], i.[Description], i.[Unit Price] 

        UNION ALL

        SELECT i.lvl + 1, 
               i.[No_], 
               i2.[No_], 
               i2.[Description], 
               CAST(bc.[Variant Code] AS NVARCHAR(20)) -- column collation
        FROM KitComponent bc
        JOIN items i ON i.[No_] = bc.[Parent Item No_]
        JOIN Item i2 ON i2.[No_] = bc.[No_] 
) 
SELECT * FROM items WHERE [Parent Item No_] = '4000540001';

检查

SELECT DATABASEPROPERTYEX(DB_NAME(), 'Collation')

和：

SELECT COLLATION_NAME,*
FROM INFORMATION_SCHEMA.COLUMNS      
WHERE table_name = 'KitComponent'
  AND column_name = 'Variant Code'

Recursive CTE Error: Types do not match

Recursive CTE Error: Types do not match

sql

tsql

sql-server

common-table-expression

type-mismatch