In this post, I am sharing different options for data type casting of PostgreSQL.
I received a couple of queries on data type casting, so sharing available options for the beginner of PostgreSQL.

Please check the below available options:
In the below demonstration, I am converting string ‘188’ into integer and adding one in the result.

Option 1:

SELECT '188'::int4 + 1;

 ?column?
----------
      189

Option 2:

SELECT int4 '188' + 1;

 ?column?
----------
      189

Option 3:

SELECT int4('188') + 1;

 ?column?
----------
      189

Option 4:

SELECT CAST('188' AS int4)+1;

 ?column?
----------
      189