How to refer to a calculated column?

[BPetro]

I thought this would be it, but it isn't - can anyone share how to refer to the calculated column "age" in the where clause -- here's the sample code -- mySql is giving the error that "age" is not a column...

Thanks!

mysql> select id,
period_diff(to_days(curdate()),to_days(entryDate)) as age
from prayerList where age < 10;
ERROR 1064: You have an error in your SQL syntax near 'where age < 10' at line 1

 

[BPetro]

My bad - actually the mySql error is:
ERROR 1054: Unknown column 'age' in 'where clause'
I copied the wrong line in my first version.

 

[swampBoogie]

You have to repeat the expression in the where clause.

 

[BNPMike]

You can use an alias in ORDER and HAVING but not WHERE. See the MySQL Appendix &quot;Problems with aliases&quot;.

 

[BPetro]

Thanks guys - that's what I needed.