case

SQL Case Statement :

SQL case statement is like "if then else " in programming.

Below are some example (high level):

Syntax:
For a particular column:

Select column1, column2, .....,

case
when < condition > then result
or
when < condition1 > and  < condition2 > then result
Else different_result --> Else is used if needed
End as result_columnName

from Table_Name

Example 1:

Select EmpID , EMP_NAME, SALARY,

Case

When salary >2000 then ‘No Bonus’

When salary >1000 and salary <2000 then ‘Bonus $100’

When salary <1000 then ‘Bonus $ 200’

End as BONUS

From Table_Name;

Example 2:

Select LOCATION , DEPARTMENT, STATE,

Case

When STATE = ‘IL’ then ‘HEAD OFFICE’

When STATE = ‘TX’ then ‘WAREHOUSE’

ELSE  ‘BRANCH OFFICE’

END  AS  OFFICE

FROM TABLE_NAME;

Example 3: Another way of writing case statement.

Select LOCATION , DEPARTMENT, STATE,

Case STATE

When ‘IL’ then ‘HEAD OFFICE’

When ‘TX’ then ‘WAREHOUSE’

ELSE  ‘BRANCH OFFICE’

END  AS  OFFICE

FROM TABLE_NAME;