如果只有值为空或 NULL，则更新 MySQL 表中的列
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Update a column in MySQL table if only the values are empty or NULL
提问by ricardo
I had previously applied this query...which works perfectly and was answered by one of the fellow members of this forum
我以前应用过这个查询......它完美地工作并且由该论坛的一位成员回答
UPDATE
jos_jbjobs_jobseeker a
INNER JOIN jos_users b ON a.email = b.email
SET
a.user_id = b.id
Now i want to use the same query adding one more condition... i.e
现在我想使用相同的查询添加一个条件......即
Set a.user_id = b.id only if a.user_id is empty ,,
仅当 a.user_id 为空时才设置 a.user_id = b.id ,,
can i apply this :
我可以申请这个吗：
if a.user_id = '' SET a.user_id = b.id ;
如果 a.user_id = '' SET a.user_id = b.id ;
?
?
回答by Teja
UPDATE
jos_jbjobs_jobseeker a
INNER JOIN jos_users b ON a.email = b.email
SET
a.user_id = b.id
WHERE a.id IS NULL OR LENGTH(a.id)=0;
回答by Ankit Sharma
Use this
用这个
UPDATE
jos_jbjobs_jobseeker a
INNER JOIN jos_users b ON a.email = b.email
SET
a.user_id = b.id
WHERE a.id ='';
If id have null values too then use this-
如果 id 也有空值，那么使用这个 -
UPDATE
jos_jbjobs_jobseeker a
INNER JOIN jos_users b ON a.email = b.email
SET
a.user_id = b.id
WHERE a.id is null or a.id ='';
回答by MISSIRIA
Try this code SQLnative it's work for me very well :
试试这个代码SQLnative 它对我来说很好用：
UPDATE table
SET field = 'New value'
WHERE field
IS NULL
OR field = ''
Update just NULLvalue or EMPTY.
只更新NULL值或EMPTY。
