IF statement in SELECT QUERY

[Canman2005]

Hi all

 

I wonder if someone can help.

 

Is it possible to add an "if" statement into a QUERY?

 

For example, I have

 

SELECT p.id, p.name, p.topic FROM people p WHERE p.type = 'Math';

 

But I want to add

 

if(p.topic == 'today') { p.date }

 

to the end of

 

SELECT p.id, p.name, p.topic

 

so it would look something like

 

SELECT p.id, p.name, p.topic, if(p.topic == 'today') { p.date } FROM people p WHERE p.type = 'Math';

 

 

So in real terms it would end up looking like either

 

SELECT p.id, p.name, p.topic FROM people p WHERE p.type = 'Math';

 

or if

 

topic equaled "today"

 

then it would use

 

SELECT p.id, p.name, p.topic,p.date FROM people p WHERE p.type = 'Math';

 

I know the above is not possible, but what would I change it to if at all possible.

 

Thanks all

 

Ed

[Mchl]

SELECT p.id, p.name, p.topic,IF(p.topic = 'today',p.date,NULL) AS date FROM people p WHERE p.type = 'Math';

[Canman2005]

thanks, that seemed to work great

 

Just another question, but is it also possible to add something like that at the end of the QUERY, so adding

 

JOIN t.things ON t.userid = p.id

 

to the end of

 

SELECT p.id, p.name, p.topic FROM people p WHERE p.type = 'Math';

 

so I guess it would be something like

 

SELECT p.id, p.name, p.topic FROM people p (p.topic = 'yesterday', JOIN t.things ON t.userid = p.id) WHERE p.type = 'Math';

 

Thanks very much

[Mchl]

Nope. You can however do:

 

SELECT p.id, p.name, p.topic, t.things
FROM people p 
LEFT JOIN 
otherTable AS t ON (t.userid = p.id AND p.topic = 'yesterday')
WHERE p.type = 'Math';

 

which would essentialy have same result.

[Canman2005]

thanks dude, worked a charm