how to convert weird varchar “time” to real time in mysql?

Question

I have a time value being stored in a database as a varchar(4) and I need to convert it to real time.

for example, if the time is \"23:59\" I want 11:59PM returned.

Answer 1

Using a table named test with a column named string and with values

2300
2100
1200
0430
0430

With query

select concat(time_format(concat(substring(string,-4,2),':',substring(string,3)),'%h:%i'),
   case when string >= 1200 then ' PM' else ' AM' end)
from test;

You get,

11:00 PM
09:00 PM
12:00 PM
04:30 AM
04:30 AM