MYSQL：在CONCAT（）函数中使用列名会产生语法错误1064

Question

I have this query

UPDATE `fitment_drums` SET `liters` = CONCAT(`liters`,'.0') WHERE `liters` LIKE '_'

Which results in this error:

#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 ''.0') FROM `fitment_drums` WHERE `liters` LIKE '_'' at line 1

When I substitute an ordinary string, eg. CONCAT ('asdf','.0') it works fine. I've tried using a select statement as an argument, and have also tried using a temporary table:

CREATE TEMPORARY TABLE t1 (SELECT * FROM `fitment_drums` WHERE liters like '_') 
UPDATE `fitment_drums` SET liters = CONCAT(t1.liters,'.0') where t1.id = id

Answer 1

Ok, so I found the "solution". I was running the query in simulation mode, which results in the error posted above. So I backed up the table and executed the query in live mode, and it worked. (for the record, I'm using phpMyAdmin)

Very strange.

Thanks to everyone who tried to help!

Answer 2

Since you revealed that you're using phpMyAdmin, you should know that temporary tables are dropped automatically as a database connection ends.

Each page view in phpMyAdmin is a separate PHP request, and thus a separate database connection.

So if you CREATE TEMPORARY TABLE in phpMyAdmin, then the temp table did not exist anymore by the time you ran your UPDATE .