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MySQL update a column with an int based on order?
The syntax is as follows to update a column with an int based on order
set @yourVariableName=0; update yourTableName set yourColumnName=(@yourVariableName:=@yourVariableName+1) order by yourColumnName ASC;
To understand the above syntax, let us create a table. The query to create a table is as follows
mysql> create table updateColumnDemo -> ( -> Id int, -> OrderCountryName varchar(100), -> OrderAmount int -> ); Query OK, 0 rows affected (1.76 sec)
Insert some records in the table using insert command.
The query is as follows
mysql> insert into updateColumnDemo(Id,OrderCountryName) values(10,'US'); Query OK, 1 row affected (0.46 sec) mysql> insert into updateColumnDemo(Id,OrderCountryName) values(20,'UK'); Query OK, 1 row affected (0.98 sec) mysql> insert into updateColumnDemo(Id,OrderCountryName) values(30,'AUS'); Query OK, 1 row affected (0.77 sec) mysql> insert into updateColumnDemo(Id,OrderCountryName) values(40,'France'); Query OK, 1 row affected (1.58 sec)
Display all records from the table using select statement.
The query is as follows
mysql> select *from updateColumnDemo;
The following is the output
+------+------------------+-------------+ | Id | OrderCountryName | OrderAmount | +------+------------------+-------------+ | 10 | US | NULL | | 20 | UK | NULL | | 30 | AUS | NULL | | 40 | France | NULL | +------+------------------+-------------+ 4 rows in set (1.00 sec)
Here is the query to update a column with an int based on order
mysql> set @sequenceNumber=0; Query OK, 0 rows affected (0.00 sec) mysql> update updateColumnDemo -> set OrderAmount=(@sequenceNumber:=@sequenceNumber+1) -> order by OrderAmount ASC; Query OK, 4 rows affected (0.25 sec) Rows matched: 4 Changed: 4 Warnings: 0
Let us check the table records once again.
The query is as follows
mysql> select *from updateColumnDemo;
The following is the output
+------+------------------+-------------+ | Id | OrderCountryName | OrderAmount | +------+------------------+-------------+ | 10 | US | 1 | | 20 | UK | 2 | | 30 | AUS | 3 | | 40 | France | 4 | +------+------------------+-------------+ 4 rows in set (0.00 sec)
Updated on: 30-Jul-2019
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