I know that SQL's CASE syntax is as follows:
CASE
WHEN search_condition THEN statement_list
[WHEN search_condition THEN statement_list] ...
[ELSE statement_list]
END CASE
However, I don't understand how this works, possibly because I'm thinking about it as about an if statement.
If I have a field in table user_role, for example, which contains names like "Manager", "Part Time" etc., how do I generate a field role_order with a different number depending on the role. In the case of this example, "if user_role = 'Manager' then role_order = 5".
Please note I am looking for a teach a man how to fish answer rather than give a man a fish answer.
Answer
CASE is more like a switch statement. It has two syntaxes you can use. The first lets you use any compare statements you want:
CASE
WHEN user_role = 'Manager' then 4
WHEN user_name = 'Tom' then 27
WHEN columnA <> columnB then 99
ELSE -1 --unknown
END
The second style is for when you are only examining one value, and is a little more succinct:
CASE user_role
WHEN 'Manager' then 4
WHEN 'Part Time' then 7
ELSE -1 --unknown
END