force cast data type colomn in postgresql code example

Example 1: how to change column type psql

ALTER TABLE table_name
ALTER COLUMN column_name [SET DATA] TYPE new_data_type;

Example 2: postgresql cast

SELECT '100'::INTEGER;
SELECT CAST ('100' AS INTEGER);

Example 3: update column data type postgres

ALTER TABLE table_name
ALTER COLUMN column_name [SET DATA] TYPE new_data_type;