Change value from 1 to Y in MySQL Select Statement using CASE?

You can use CASE from MySQL to change value from 1 to Y. Let us first create a table. The query to create a table is as follows:

mysql> create table changeValuefrom1toY
   -> (
   -> Id int NOT NULL AUTO_INCREMENT,
   -> isValidAddress tinyint(1),
   -> PRIMARY KEY(Id)
   -> );
Query OK, 0 rows affected (0.76 sec)

Now you can insert some records in the table using insert command. The query is as follows:

mysql> insert into changeValuefrom1toY(isValidAddress) values(1);
Query OK, 1 row affected (0.22 sec)
mysql> insert into changeValuefrom1toY(isValidAddress) values(0);
Query OK, 1 row affected (0.16 sec)
mysql> insert into changeValuefrom1toY(isValidAddress) values(1);
Query OK, 1 row affected (0.19 sec)
mysql> insert into changeValuefrom1toY(isValidAddress) values(1);
Query OK, 1 row affected (0.15 sec)
mysql> insert into changeValuefrom1toY(isValidAddress) values(1);
Query OK, 1 row affected (0.16 sec)
mysql> insert into changeValuefrom1toY(isValidAddress) values(0);
Query OK, 1 row affected (0.12 sec)
mysql> insert into changeValuefrom1toY(isValidAddress) values(1);
Query OK, 1 row affected (0.49 sec)

Display all records from the table using select statement. The query is as follows:

mysql> select *from changeValuefrom1toY;

The following is the output:

+----+----------------+
| Id | isValidAddress |
+----+----------------+
|  1 |              1 |
|  2 |              0 |
|  3 |              1 |
|  4 |              1 |
|  5 |              1 |
|  6 |              0 |
|  7 |              1 |
+----+----------------+
7 rows in set (0.00 sec)

The following is the query to work with CASE:

mysql> select *,case
   -> when isValidAddress=1 THEN 'Y'
   -> ELSE isValidAddress
   -> END AS Answer
   -> from changeValuefrom1toY;

The following is the output:

+----+----------------+--------+
| Id | isValidAddress | Answer |
+----+----------------+--------+
|  1 |              1 | Y      |
|  2 |              0 | 0      |
|  3 |              1 | Y      |
|  4 |              1 | Y      |
|  5 |              1 | Y      |
|  6 |              0 | 0      |
|  7 |              1 | Y      |
+----+----------------+--------+
7 rows in set (0.00 sec)