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MySQL queries to update date records with NULL values
You can use IFNULL() for this. Let us first create a table −
mysql> create table DemoTable -> ( -> added_date date, -> updated_date date -> ); Query OK, 0 rows affected (0.95 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values('2019-01-10','2019-06-01');
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable values('2019-05-19',NULL);
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values(NULL,'2019-09-05');
Query OK, 1 row affected (0.18 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+------------+--------------+ | added_date | updated_date | +------------+--------------+ | 2019-01-10 | 2019-06-01 | | 2019-05-19 | NULL | | NULL | 2019-09-05 | +------------+--------------+ 3 rows in set (0.00 sec)
Case 1 − If you want the result in descending order.
Here is the query to select row with added_date and updated_date.
mysql> select *from DemoTable order by ifnull(updated_date,added_date) desc;
This will produce the following output −
+------------+--------------+ | added_date | updated_date | +------------+--------------+ | NULL | 2019-09-05 | | 2019-01-10 | 2019-06-01 | | 2019-05-19 | NULL | +------------+--------------+ 3 rows in set (0.00 sec)
Case 2 − If you want the result in ascending order.
Here is the query to select row with added_date and updated_date −
mysql> select *from DemoTable order by ifnull(updated_date,added_date);
This will produce the following output −
+------------+--------------+ | added_date | updated_date | +------------+--------------+ | 2019-05-19 | NULL | | 2019-01-10 | 2019-06-01 | | NULL | 2019-09-05 | +------------+--------------+ 3 rows in set (0.00 sec)
Updated on: 30-Jul-2019
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