MySQL query to subtract date records with week day and display the weekday with records

For this, you can use DATE_FORMAT(). Let us first create a table −

mysql> create table DemoTable1820
     (
     AdmissionDate varchar(20)
     );
Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1820 values('20/10/2019');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1820 values('19/12/2018');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1820 values('16/04/2017');
Query OK, 1 row affected (0.00 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1820;

This will produce the following output −

+---------------+
| AdmissionDate |
+---------------+
| 20/10/2019    |
| 19/12/2018    |
| 16/04/2017    |
+---------------+
3 rows in set (0.00 sec)

Here is the query to subtract date records with week day and display week day name along with records −

mysql> select DATE_FORMAT(SUBDATE(STR_TO_DATE(AdmissionDate,'%d/%m/%y'), WEEKDAY(STR_TO_DATE(AdmissionDate,'%d/%m/%y'))), '%a %d %b') from DemoTable1820;

This will produce the following output −

+-------------------------------------------------------------------------------------------------------------------------+
| DATE_FORMAT(SUBDATE(STR_TO_DATE(AdmissionDate,'%d/%m/%y'), WEEKDAY(STR_TO_DATE(AdmissionDate,'%d/%m/%y'))), '%a %d %b') |
+-------------------------------------------------------------------------------------------------------------------------+
| Mon 19 Oct                                                                                                              |
| Mon 14 Dec                                                                                                              |
| Mon 13 Apr                                                                                                              |
+-------------------------------------------------------------------------------------------------------------------------+
3 rows in set, 6 warnings (0.00 sec)