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Reorder keys after deleting a record from MySQL table?
For this, use UPDATE command with some mathematical calculations. To delete an id, use the DELETE. Let us first create a table −
mysql> create table DemoTable1476 -> ( -> Id int -> ); Query OK, 0 rows affected (0.81 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable1476 values(10); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable1476 values(20); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable1476 values(30); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable1476 values(40); Query OK, 1 row affected (0.12 sec)
Display all records from the table using select statement −
mysql> select * from DemoTable1476;
This will produce the following output −
+------+ | Id | +------+ | 10 | | 20 | | 30 | | 40 | +------+ 4 rows in set (0.00 sec)
Following is the query to delete some id from the table −
mysql> delete from DemoTable1476 where Id=30; Query OK, 1 row affected (0.16 sec)
After deleting, the table records are as follows −
mysql> select * from DemoTable1476;
This will produce the following output −
+------+ | Id | +------+ | 10 | | 20 | | 40 | +------+ 3 rows in set (0.00 sec)
Following is the query to reorder keys after deleting from MySQL table −
mysql> update DemoTable1476 set Id=Id-10 where Id > 30; Query OK, 1 row affected (0.14 sec) Rows matched: 1 Changed: 1 Warnings: 0
Let us check the table records once again −
mysql> select * from DemoTable1476;
This will produce the following output −
+------+ | Id | +------+ | 10 | | 20 | | 30 | +------+ 3 rows in set (0.00 sec)
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