I have a varchar field in a table which contains dates in yyyy-mm-dd format.
The problem is that some have entered invalid dates like 1975-01-00 and I
want to convert it to a date field to avoid this nonsense. Is there a way to
test for failure of a type conversion and insert a NULL on failure?
Hi,
If you are using 8.0 or above you could write a plpgsql function and use
a for select loop with a exception handler. In the loop try casting the
column in question to date type and if a error is raised because of a
invalid date set the column value to null.
See this section in the docs:
http://www.postgresql.org/docs/8.1/static/plpgsql-control-structures.html#PLPGSQL-ERROR-TRAPPING
After you have cleaned up the bad dates, then change the column to a
date type.
Note: I have not tested this, but I think it should work :-)
Later,
--
Tony Caduto
AM Software Design
Home of PG Lightning Admin for Postgresql
http://www.amsoftwaredesign.com
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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
match
