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SELECT increment counter in MySQL?
To select increment counter in MySQL, first you need to declare and initialize a variable. The syntax is as follows −
set @anyVariableName=0; select yourColumnName, @anyVariableName:=@anyVariableName+1 as anyVariableName from yourTableName;
To understand the above syntax and set an increment counter, let us first create a table. The query to create a table is as follows.
mysql> create table incrementCounterDemo -> ( -> Name varchar(100) -> ); Query OK, 0 rows affected (1.01 sec)
Insert some records in the table using insert command. The query is as follows.
mysql> insert into incrementCounterDemo values('John');
Query OK, 1 row affected (0.18 sec)
mysql> insert into incrementCounterDemo values('Carol');
Query OK, 1 row affected (0.20 sec)
mysql> insert into incrementCounterDemo values('David');
Query OK, 1 row affected (0.14 sec)
mysql> insert into incrementCounterDemo values('Mike');
Query OK, 1 row affected (0.21 sec)
mysql> insert into incrementCounterDemo values('Bob');
Query OK, 1 row affected (0.12 sec)
mysql> insert into incrementCounterDemo values('Sam');
Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement. The query is as follows −
mysql> select *from incrementCounterDemo;
The following is the output.
+-------+ | Name | +-------+ | John | | Carol | | David | | Mike | | Bob | | Sam | +-------+ 6 rows in set (0.00 sec)
Set variable
mysql> set @counter=0; Query OK, 0 rows affected (0.00 sec)
Now select the increment counter.
mysql> select Name, -> @counter:=@counter+1 as IncrementingValuebyOne -> from incrementCounterDemo;
The following is the output.
+-------+------------------------+ | Name | IncrementingValuebyOne | +-------+------------------------+ | John | 1 | | Carol | 2 | | David | 3 | | Mike | 4 | | Bob | 5 | | Sam | 6 | +-------+------------------------+ 6 rows in set (0.00 sec)
Updated on: 25-Jun-2020
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