[170] the PostgreSQL 10 field type is changed from string to integer, and the error column cannot be cast automatically to type integer is reported

Error recurrence

The original field type is character varying Change to integer

ALTER TABLE table_name ALTER COLUMN column_name TYPE integer

PostgreSQL 10 Report errors ：

ERROR:  column "column_name" cannot be cast automatically to type integer
HINT:  You might need to specify "USING column_name::integer".
SQL state: 42804

resolvent

Make sure there is no string data in the field to be modified , If any, it needs to be set to NULL.

Change the statement of modifying the field to the following ：

ALTER TABLE table_name ALTER COLUMN column_name TYPE integer using column_name::integer;

Note that there must be using column_name::integer Otherwise, an error will be reported .