Insert sequential number in MySQL?

MySQLMySQLi Database

You can insert sequential number in MySQL using session variable. The syntax is as follows −

SELECT @anyVariableName − = anyIntegerValue;
UPDATE yourTableName SET yourColumnName = @anyVariableName − = @anyVariableName+IncrementStep;

To understand the above syntax, let us create a table. The query to create a table is as follows −

mysql> create table SequentialNumberDemo
   -> (
   -> SequentialNumber int not null
   -> );
Query OK, 0 rows affected (0.84 sec)

Insert records in the table using insert command. The query is as follows −

mysql> insert into SequentialNumberDemo values(100);
Query OK, 1 row affected (0.11 sec)

mysql> insert into SequentialNumberDemo values(10);
Query OK, 1 row affected (0.22 sec)

mysql> insert into SequentialNumberDemo values(9);
Query OK, 1 row affected (0.15 sec)

mysql> insert into SequentialNumberDemo values(60);
Query OK, 1 row affected (0.11 sec)

mysql> insert into SequentialNumberDemo values(50);
Query OK, 1 row affected (0.14 sec)

mysql> insert into SequentialNumberDemo values(40);
Query OK, 1 row affected (0.13 sec)

Display all records from the table using select statement. The query is as follows −

mysql> select *from SequentialNumberDemo;

The following is the output −

+------------------+
| SequentialNumber |
+------------------+
|              100 |
|               10 |
|                9 |
|               60 |
|               50 |
|               40 |
+------------------+
6 rows in set (0.00 sec)

Look at the above output, the number is not in a sequential order. Here is the query to get the sequential number beginning from 1. At first, set the sequence −

mysql> select @sequence: = 0;

The output −

+---------------+
| @sequence:= 0 |
+---------------+
|             0 |
+---------------+
1 row in set (0.03 sec)

Now, the query to update and begin the sequence from 1 −

mysql> update SequentialNumberDemo set SequentialNumber = @sequence − = @sequence+1;
Query OK, 6 rows affected (0.15 sec)
Rows matched − 6 Changed − 6 Warnings − 0

Check the table records once again. The query is as follows −

mysql> select *from SequentialNumberDemo;

The following is the output −

+------------------+
| SequentialNumber |
+------------------+
| 1                |
| 2                |
| 3                |
| 4                |
| 5                |
| 6                |
+------------------+
6 rows in set (0.00 sec)
raja
Published on 01-Feb-2019 05:58:07
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