sql - Are PostgreSQL column names case-sensitive?

Question

I have a db table say, persons in Postgres handed down by another team that has a column name say, "first_Name". Now am trying to use PG commander to query this table on this column-name.

select * from persons where first_Name="xyz";

And it just returns

ERROR: column "first_Name" does not exist

Not sure if I am doing something silly or is there a workaround to this problem that I am missing?

Answer 1

Identifiers (including column names) that are not double-quoted are folded to lowercase in PostgreSQL. Column names that were created with double-quotes and thereby retained uppercase letters (and/or other syntax violations) have to be double-quoted for the rest of their life:

"first_Name"

Values (string literals / constants) are enclosed in single quotes:

'xyz'

So, yes, PostgreSQL column names are case-sensitive (when double-quoted):

SELECT * FROM persons WHERE "first_Name" = 'xyz';

Read the manual on identifiers here.

My standing advice is to use legal, lower-case names exclusively so double-quoting is not needed.