postgreSQL 将列数据类型更改为没有时区的时间戳

我想把一列数据从文本改成时间戳类型.我的数据中没有时区.我的数据格式是28-03-17 17:22，包括时间和日期，但没有时区.换句话说，我所有的数据都在同一个时区.我该怎么做？

我在下面try 了多种方法，但仍然找不到正确的方法.希望你能帮助我.

当然，如果我的问题得到解决，我可以建一张新桌子.

alter table AB
alter create_time type TIMESTAMP;

ERROR:  column "create_time" cannot be cast automatically to type timestamp without time zone
HINT:  You might need to specify "USING create_time::timestamp without time zone".
********** Error **********

ERROR: column "create_time" cannot be cast automatically to type timestamp without time zone
SQL state: 42804
Hint: You might need to specify "USING create_time::timestamp without time zone".

alter table AB
alter create_time type TIMESTAMP without time zone;

ERROR:  column "create_time" cannot be cast automatically to type timestamp without time zone
HINT:  You might need to specify "USING create_time::timestamp without time zone".
********** Error **********

ERROR: column "create_time" cannot be cast automatically to type timestamp without time zone
SQL state: 42804
Hint: You might need to specify "USING create_time::timestamp without time zone".

alter table AB
alter create_time::without time zone type TIMESTAMP;

ERROR:  syntax error at or near "::"
LINE 2:  alter create_time::without time zone type TIMESTAM
                          ^
********** Error **********

ERROR: syntax error at or near "::"
SQL state: 42601
Character: 50

alter table AB
alter create_time UTC type TIMESTAMP;

ERROR:  syntax error at or near "UTC"
LINE 2: alter create_time UTC type TIMESTAMP;
                          ^
********** Error **********

ERROR: syntax error at or near "UTC"
SQL state: 42601
Character: 50