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MySQL UPDATE query where id is highest AND field is equal to variable?
The syntax is as follows
update yourTableName set yourColumnName1=yourValue where yourColumnName2=yourValue order by yourIdColumnName DESC LIMIT 1;
To understand the above syntax, let us create a table. The query to create a table is as follows
mysql> create table UpdateWithHighestDemo -> ( -> UserId int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> UserStatus tinyint, -> UserRank int -> ); Query OK, 0 rows affected (0.61 sec)
Insert some records in the table using insert command.
The query is as follows
mysql> insert into UpdateWithHighestDemo(UserStatus,UserRank) values(1,78); Query OK, 1 row affected (0.12 sec) mysql> insert into UpdateWithHighestDemo(UserStatus,UserRank) values(0,118); Query OK, 1 row affected (0.18 sec) mysql> insert into UpdateWithHighestDemo(UserStatus,UserRank) values(1,223); Query OK, 1 row affected (0.62 sec) mysql> insert into UpdateWithHighestDemo(UserStatus,UserRank) values(1,225); Query OK, 1 row affected (0.12 sec) mysql> insert into UpdateWithHighestDemo(UserStatus,UserRank) values(0,227); Query OK, 1 row affected (0.14 sec) mysql> insert into UpdateWithHighestDemo(UserStatus,UserRank) values(0,230); Query OK, 1 row affected (0.17 sec)
Display all records from the table using select statement.
The query is as follows
mysql> select *from UpdateWithHighestDemo;
The following is the output
+--------+------------+----------+ | UserId | UserStatus | UserRank | +--------+------------+----------+ | 1 | 1 | 78 | | 2 | 0 | 118 | | 3 | 1 | 223 | | 4 | 1 | 225 | | 5 | 0 | 227 | | 6 | 0 | 230 | +--------+------------+----------+ 6 rows in set (0.00 sec)
Here is the query to update column
mysql> update UpdateWithHighestDemo -> set UserStatus=1 where UserRank=230 order by UserId DESC LIMIT 1; Query OK, 1 row affected (0.19 sec) Rows matched: 1 Changed: 1 Warnings: 0
Let us check and display records from the table using select statement.
The query is as follows
mysql> select *from UpdateWithHighestDemo;
The following is the output
+--------+------------+----------+ | UserId | UserStatus | UserRank | +--------+------------+----------+ | 1 | 1 | 78 | | 2 | 0 | 118 | | 3 | 1 | 223 | | 4 | 1 | 225 | | 5 | 0 | 227 | | 6 | 1 | 230 | +--------+------------+----------+ 6 rows in set (0.00 sec)
Now if you want to update with highest id then ORDER BY clause is useful. In the above sample output the highest ‘UserId’=6 and UserStatus is 1.
Let us update UserStatus to 0.
The query is as follows
mysql> update UpdateWithHighestDemo -> set UserStatus=0 order by UserId DESC LIMIT 1; Query OK, 1 row affected (0.18 sec) Rows matched: 1 Changed: 1 Warnings: 0
Check the records from the table using select statement.
The query is as follows
mysql> select *from UpdateWithHighestDemo; +--------+------------+----------+ | UserId | UserStatus | UserRank | +--------+------------+----------+ | 1 | 1 | 78 | | 2 | 0 | 118 | | 3 | 1 | 223 | | 4 | 1 | 225 | | 5 | 0 | 227 | | 6 | 0 | 230 | +--------+------------+----------+ 6 rows in set (0.00 sec)
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