As variable in MYSQL query

Question

I am little new in mysql database. My query is like this and its working fine

SELECT visitor_sent * 100 / visitor_quantity as percentage FROM `tbl_orders` WHERE oid =15

But I want it extend to use percentage variable in where clause but its not working.

SELECT visitor_sent * 100 / visitor_quantity as percentage FROM `tbl_orders` WHERE oid =15 AND percentage < 20

its giving me unknown column percentage error. Let me know if anyone here can help me for correct the query.

Thanks!

score 2 · Accepted Answer · answered Jan 18 '22 at 11:05

2

You need to use HAVING instead of WHERE when you want to check on an alias

SELECT visitor_sent * 100 / visitor_quantity as percentage FROM `tbl_orders` WHERE oid =15 HAVING percentage < 20

answered Jan 18 '22 at 11:05

Thallius

Note that this is a MySQL special trick. Will not work on other platforms. – jarlh Jan 18 '22 at 11:08
Yes that might be important – Thallius Jan 18 '22 at 11:08
if I use the query with Having, its giving me empty result – Vidhi Sharma Jan 18 '22 at 11:12
sorry its worked! Thanks a lot! – Vidhi Sharma Jan 18 '22 at 11:16
Would be nice if you accept the answer then. thanks – Thallius Jan 18 '22 at 11:22
I have done as well upvoted! – Vidhi Sharma Jan 18 '22 at 12:23

1 Answers1