psql column doesn't exist but it does

Question

I am trying to select a single column in my data table using raw SQL in a postgresql database from the psql command line. I am getting an error message that says the column does not exist. Then it gives me a hint to use the exact column that I referenced in the select statement. Here is the query:

SELECT insider_app_ownershipdocument.transactionDate FROM insider_app_ownershipdocument;

Here is the error message:

ERROR:  column insider_app_ownershipdocument.transactiondate does not exist
SELECT insider_app_ownershipdocument.transactionDate FROM in...
HINT:  Perhaps you meant to reference the column "insider_app_ownershipdocument.transactionDate".

I have no idea why this is not working.

Answer 1

(Postgres) SQL converts names automatically to lower case although it support case-sensitive names. So

SELECT insider_app_ownershipdocument.transactionDate FROM insider_app_ownershipdocument;

will be aquivalent to:

SELECT insider_app_ownershipdocument.transactiondate FROM insider_app_ownershipdocument;

You should protect the column name with double quotes to avoid this effect:

SELECT insider_app_ownershipdocument."transactionDate" FROM insider_app_ownershipdocument;