Question

I have an addresses table with ZIP code field which has type VARCHAR.
I need to select all addresses form this table using ZIP codes range.
If I used next code:

select * from address where cast(zip as bigint) between 90210 and 90220

I get an error on fields where ZIP code cann’t be cast as bigint.

How I can resolve this issue?

Answer 1

Derive a version of the zip column that is a bigint if the zip value is numeric, and null otherwise, and then test that.

So sth like

select * from address
where case when zip ~ '^[0-9]+$' then cast(zip as bigint) end between 90210 and 90220

To make this query efficient, you can create an index on this expression:

create index address_zip_idx on address(cast(zip as bigint)) where zip ~ '^[0-9]+$';
-- this query can now use that index
select * from address
where zip ~ '^[0-9]+$' and cast(zip as bigint) between 90210 and 90220;