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Implement MySQL CASE statement with WHEN clause
CASE statement with the WHEN clause is used to work around conditions. Following is the syntax−
select *, case when yourCondition then yourStatement when yourCondition then yourStatement . . else yourStatement from yourTableName;
Let us first create a table −
mysql> create table DemoTable -> ( -> StudentName varchar(20), -> StudentMarks int -> ); Query OK, 0 rows affected (0.77 sec)
Insert some records in the table using insert command −
mysql> insert into DemoTable values('Chris',78);
Query OK, 1 row affected (0.20 sec)
mysql> insert into DemoTable values('Robert',88);
Query OK, 1 row affected (0.14 sec)
mysql> insert into DemoTable values('Mike',75);
Query OK, 1 row affected (0.19 sec)
mysql> insert into DemoTable values('Sam',98);
Query OK, 1 row affected (0.16 sec)Display all records from the table using select statement −
mysql> select *from DemoTable;
This will produce the following output −
+-------------+--------------+ | StudentName | StudentMarks | +-------------+--------------+ | Chris | 78 | | Robert | 88 | | Mike | 75 | | Sam | 98 | +-------------+--------------+ 4 rows in set (0.00 sec)
Here is the query to implement MySQL CASE WHEN −
mysql> select *, -> case when StudentMarks > 90 then 'Very Good Score' -> when StudentMarks > 80 then 'Good Score' -> else -> 'Not Good' -> end as Status -> from DemoTable;
This will produce the following output −
+-------------+--------------+-----------------+ | StudentName | StudentMarks | Status | +-------------+--------------+-----------------+ | Chris | 78 | Not Good | | Robert | 88 | Good Score | | Mike | 75 | Not Good | | Sam | 98 | Very Good Score | +-------------+--------------+-----------------+ 4 rows in set (0.00 sec)
Updated on: 13-Dec-2019
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