Let us first create a table −
mysql> create table DemoTable -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Subject varchar(100) -> ); Query OK, 0 rows affected (0.76 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable(Subject) values('C'); Query OK, 1 row affected (0.13 sec) mysql> insert into DemoTable(Subject) values('MongoDB'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable(Subject) values('Java'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(Subject) values('MongoDB'); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable(Subject) values('Python'); Query OK, 1 row affected (0.19 sec) mysql> insert into DemoTable(Subject) values('MongoDB'); Query OK, 1 row affected (0.16 sec)
Display all records from the table using select statement −
mysql> select *from DemoTable;
Output
+----+---------+ | Id | Subject | +----+---------+ | 1 | C | | 2 | MongoDB | | 3 | Java | | 4 | MongoDB | | 5 | Python | | 6 | MongoDB | +----+---------+ 6 rows in set (0.00 sec)
Here is the query to update every second row string −
mysql> update DemoTable set Subject=replace(Subject,'MongoDB','MySQL') where Id%2=0; Query OK, 3 rows affected (0.17 sec) Rows matched: 3 Changed: 3 Warnings: 0
Let us check all records from the table −
mysql> select *from DemoTable;
Output
+----+---------+ | Id | Subject | +----+---------+ | 1 | C | | 2 | MySQL | | 3 | Java | | 4 | MySQL | | 5 | Python | | 6 | MySQL | +----+---------+ 6 rows in set (0.00 sec)