Set special characters on values if condition is true in MySQL?

For conditions, use IF(). Let us first create a table −

mysql> create table DemoTable637
   (ClientId int NOT NULL AUTO_INCREMENT PRIMARY KEY,ClientName varchar(100),ClientAge int
);
Query OK, 0 rows affected (0.82 sec)

Insert some records in the table using insert command −

mysql> insert into DemoTable637(ClientName,ClientAge) values('Chris',23);
Query OK, 1 row affected (0.17 sec)
mysql> insert into DemoTable637(ClientName,ClientAge) values('Robert',24);
Query OK, 1 row affected (0.13 sec)
mysql> insert into DemoTable637(ClientName,ClientAge) values('David',57);
Query OK, 1 row affected (0.20 sec)
mysql> insert into DemoTable637(ClientName,ClientAge) values('Carol',60);
Query OK, 1 row affected (0.13 sec)

Display all records from the table using select statement −

mysql> select *from DemoTable637;

This will produce the following output −

+----------+------------+-----------+
| ClientId | ClientName | ClientAge |
+----------+------------+-----------+
|        1 | Chris      |        23 |
|        2 | Robert     |        24 |
|        3 | David      |        57 |
|        4 | Carol      |        60 |
+----------+------------+-----------+
4 rows in set (0.00 sec)

Following is the query to set special characters if condition is true −

mysql> select if(ClientName IS NOT NULL AND ClientAge > 50,ClientName,'-------------') from DemoTable637;

This will produce the following output −

+--------------------------------------------------------------------------+
| if(ClientName IS NOT NULL AND ClientAge > 50,ClientName,'-------------') |
+--------------------------------------------------------------------------+
| -------------                                                            |
| -------------                                                            |
| David                                                                    |
| Carol                                                                    |
+--------------------------------------------------------------------------+
4 rows in set (0.00 sec)