PostgreSQL: Select data with a like on timestamp field

Question

I am trying to select data from a table, using a "like" on date field "date_checked" (timestamp). But I have this error :

SQLSTATE[42883]: Undefined function: 7 ERROR:  operator does not exist: timestamp without time zone 

My request is :

SELECT my_table.id FROM my_table WHERE my_table.date_checker LIKE '2011-01-%' 

I don't want to use :

SELECT my_table.id FROM my_table WHERE my_table.date_checker >= '2011-01-01 00:00:00'      AND  my_table.date_checker < '2011-02-01 00:00:00' 

Answer 1

It's all very well not "wanting to use" < and > with timestamps, but those operators can be converted into index scans, and a string-match... well, it can, but EWWWW.

Well, the error is occurring because you need to explicitly convert the timestamp to a string before using a string operation on it, e.g.:

date_checker::text LIKE '2011-01-%' 

and I suppose you could then create an index on (date_checker::text) and that expression would become an index scan but.... EWWWW.

Answer 2

Try this:

SELECT my_table.id FROM my_table WHERE CAST(my_table.date_checker AS VARCHAR) LIKE '2011-01-%';