Question

我正在执行数据迁移到具有非常不同结构的新数据库。使用SQL Server＆amp; T-SQL。

这是我的表的一个SQLFiddle示例，到目前为止我已经到了： http://sqlfiddle.com/#!18/d179b/1

我有四张桌子：

CallNotes ：

    Id, uniqueidentifier
    OldCallRecordId, int -- Used for migrating only, not in final
    Content, nvarchar(100)

CallTopics ：

    Id, uniqueidentifier
    Name, nvarchar(50)

CallNoteCallTopics ：

    CallNoteId, uniqueidentifier
    CallTopicId, uniqueidentifier

OldCallRecords ：

    Id, int
    CallTopicOne, bit
    CallTopicTwo, bit
    CallTopicThree, bit
    CallTopicFour, bit

我想在true声明中将CallTopic* OldCallRecords的所有CallNoteCallTopics.CallTopicId INSERT值转换为CASE

所有其他表格中都包含数据。

我目前正在尝试使用INSERT INTO CallNoteCallTopics SELECT CallNotes.Id, CASE WHEN OldCallRecords.CallTopicOne = 1 THEN (SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic One') WHEN OldCallRecords.CallTopicTwo = 1 THEN (SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic Two') WHEN OldCallRecords.CallTopicThree = 1 THEN (SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic Three') WHEN OldCallRecords.CallTopicFour = 1 THEN (SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic Four') END FROM OldCallRecords LEFT JOIN CallNotes ON CallNotes.OldCallRecordId = OldCallRecords.Id语句，但这只会让我获得第一个真正的价值，这不是我想要的：

__init__(..)

Answer 1

发生这种情况是因为当其中一个候选列点击对应CASE WHEN然后输出时，将不会再次检查同一行。

您可以尝试使用UNION

INSERT INTO CallNoteCallTopics
 SELECT
   CallNotes.Id
   ,(SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic One') as CallTopicId
 FROM OldCallRecords
 LEFT JOIN CallNotes
 ON CallNotes.OldCallRecordId = OldCallRecords.Id
 WHERE OldCallRecords.CallTopicOne = 1

UNION 

 SELECT
   CallNotes.Id
   ,(SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic Two') as CallTopicId
 FROM OldCallRecords
 LEFT JOIN CallNotes
 ON CallNotes.OldCallRecordId = OldCallRecords.Id
 WHERE OldCallRecords.CallTopicTwo = 1

UNION 

 SELECT
   CallNotes.Id
   ,(SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic Three') as CallTopicId
 FROM OldCallRecords
 LEFT JOIN CallNotes
 ON CallNotes.OldCallRecordId = OldCallRecords.Id
 WHERE OldCallRecords.CallTopicThree = 1

UNION 

 SELECT
   CallNotes.Id
   ,(SELECT CallTopics.Id FROM CallTopics WHERE CallTopics.Name = 'Call Topic Four') as CallTopicId
 FROM OldCallRecords
 LEFT JOIN CallNotes
 ON CallNotes.OldCallRecordId = OldCallRecords.Id
 WHERE OldCallRecords.CallTopicFour = 1

如何根据不同表中的多个列将多行插入到“多对多”表中

1 个答案: