Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
281 views
in Technique[技术] by (71.8m points)

sql - MySQL UPDATE syntax with multiple tables using WHERE clause

Case:

How to update table1 with data from table2 where id is equal?

Problem:

When I run the following update statement, it updates all the records in table1 (even where the id field in table1 does not exist in table2).

How can I use the the multiple update table syntax, to update ONLY the records in table1 ONLY where the id is present in table2 and equal?

UPDATE table1,table2
SET table1.value=table2.value 
WHERE table2.id=table1.id

Thanks in advance.

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

here's the correct syntax of UPDATE with join in MySQL

UPDATE  table1 a
        INNER JOIN table2 b
            ON a.ID = b.ID
SET     a.value = b.value 

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...