How move content fieldA to fieldB WHEN fieldC='X'

[JanHolland]

I tried:
UPDATE `tablename` SET `fieldA` = `fieldB`
WHERE fieldC = 'X';

in different combinations of fieldnames with/without _`_

I got: "Getroffen rijen: 0 (Query duurde 0.0011 sec)".

In normal language:
The group tablerows where fieldC has the value X
should have the content of fieldB in fieldA.

I found the technical term 'self-join' but
couldnt do much with it.\(Neither did I find examples that came close.

TIA4 any help ...

JanHolland

[ronverdonk]

I ran the same update and it worked perfectly allright, as it should, with and without back-ticks!

UPDATE `tablename` SET `fieldA` = `fieldB` 
WHERE fieldC = 'X';
 

Maybe your fieldC does not contain a value 'X' or has a different data type.

Ronald :cool:

[JanHolland]

Another provider with a more modern MySQL
reported:
"MySQL answered:


#1054 - Unknown column 'X' in 'where clause'"

[ronverdonk]

Can't be that modern. How do you get an 'unknown column X' where you don't use a column X? You must use a different query then the one shown.

Ronald :cool: