How to subtract from the current timestamp the number of hours stored in a column?

Question

I am trying to retrieve data from a column with integer values by getting the difference between the current_timestamp and the values in the column. This works in DB2 by simply stating the value as hour

TRANS_DATETIME > (CURRENT_TIMESTAMP - my_column_alias HOURS).

However using the same line in PostgreSQL returns the error below. Any ideas on how to modify query for PostgreSQL?

SQL Error [42883]: ERROR: operator does not exist: timestamp with time zone - integer¶
Hint: No operator matches the given name and argument types. You might need to add explicit type casts.¶

Answer 1

You can use make_interval() to construct an interval from a given number of hours that's stored in a column:

trans_datetime > current_timestamp - make_interval(hours => my_column)