STR_TO_DATE as column, but column not found?

You can use having clause. Let us first create a table −

mysql> create table DemoTable    -> (    -> AdmissionDate varchar(100)    -> ); Query OK, 0 rows affected (0.55 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable values('10/12/2017'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('01/11/2018'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values('31/01/2019'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('09/06/2019'); Query OK, 1 row affected (0.16 sec) mysql> insert into DemoTable values('19/04/2019'); Query OK, 1 row affected (0.23 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable;

Output

+---------------+ | AdmissionDate | +---------------+ | 10/12/2017    | | 01/11/2018    | | 31/01/2019    | | 09/06/2019    | | 19/04/2019    | +---------------+ 5 rows in set (0.00 sec)

Following is the query to STR_TO_DATE as column −

mysql> select STR_TO_DATE(AdmissionDate, '%d/%m/%Y') as newDate from DemoTable    -> having newDate >= '2019-01-01';

Output

+------------+ | newDate    | +------------+ | 2019-01-31 | | 2019-06-09 | | 2019-04-19 | +------------+ 3 rows in set (0.00 sec)