How to add dynamic column in mysql

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SELECT *,CAST when likemsg.msgid = '' THEN 1 from msg LEFT JOIN likemsg ON msg.id=likemsg.msgid

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Error
SQL query: Documentation

SELECT * , CAST
WHEN likemsg.msgid = ''
THEN 1
FROM msg
LEFT JOIN likemsg ON msg.id = likemsg.msgid
LIMIT 0 , 30

MySQL said: Documentation

#1064 - You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'when likemsg.msgid = '' THEN 1 from msg LEFT JOIN likemsg ON msg.id=likemsg.msgi' at line 1

What I have tried:

SELECT *,CAST when likemsg.msgid = '' THEN 1 from msg LEFT JOIN likemsg ON msg.id=likemsg.msgid

Posted 26-Feb-16 17:05pm

Arpit6016

Updated 27-Feb-16 0:33am

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RDBurmon · Answer 1 · 2016-02-27T00:33:00

Solution 1

small correction -

SELECT *,
IF(likemsg.msgid = '' , 1, likemsg.msgid ) as msgid
from msg LEFT JOIN likemsg ON msg.id=likemsg.msgid

Read this post - very helpful

mysql - 'IF' in 'SELECT' statement - choose output value based on column values - Stack Overflow[^]

Posted 27-Feb-16 0:33am

RDBurmon