Mysql - selecting year from a unix timestamp

Question

I am using this:

SELECT FROM_UNIXTIME(my_unix_timestamp_column, \'%Y\') AS year FROM table_name WHERE year = 2009;

but it gives me an error

Answer 1

You can't use a column created the SELECT section in your WHERE clause

replace the year variable in your where clause with the actual function to create that column (aka FROM_UNIXTIME(my_unix_timestamp_column, '%Y') ) and you should be fine.

This is because the SELECT section of your query isn't executed until the WHERE section has finished matching rows to return.