How to replace a particular character in a MySQL column?

To replace a particular character, use REPLACE() and to update, use the UPDATE command. Let us first create a table −

mysql> create table DemoTable1899
   (
   Code varchar(20)
   );
Query OK, 0 rows affected (0.00 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable1899 values('John_123');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1899 values('32189_Sam_987');
Query OK, 1 row affected (0.00 sec)
mysql> insert into DemoTable1899 values('Miller_David_456_909');
Query OK, 1 row affected (0.00 sec)

Display all records from the table using select statement −

mysql> select * from DemoTable1899;

This will produce the following output −

+----------------------+
| Code                 |
+----------------------+
| John_123             |
| 32189_Sam_987        |
| Miller_David_456_909 |
+----------------------+
3 rows in set (0.00 sec)

Here is the query to replace a particular character −

mysql> update DemoTable1899 set Code=replace(Code,'_','');
Query OK, 3 rows affected (0.00 sec)
Rows matched: 3  Changed: 3 Warnings: 0

Let us check the table records once again:

mysql> select * from DemoTable1899;

This will produce the following output −

+-------------------+
| Code              |
+-------------------+
| John123           |
| 32189Sam987       |
| MillerDavid456909 |
+-------------------+
3 rows in set (0.00 sec)