Case has two formats: Simple Case Case function and search function.
1. Simple Case function:
CASE sex
WHEN‘1’THEN‘男’
WHEN‘0’THEN‘女’
ELSE 'Other' END
2.Case search function:
CASE WHEN sex=‘1’THEN‘男’
WHEN sex=‘0’THEN‘女’
ELSE 'Other' END
Clearly, the simple raw Case function in simple, but it only applies to the comparison of such single-field single value, while the search function Case advantage that the comparison for all cases.
Note that there is a problem, Case function after a qualifying meet the remaining conditions will be automatically ignored, so even if a number of conditions are met, the implementation process only recognize the first condition.
In use CASE WHEN, it can not as a field name field, the field values according to the condition confirmation, when required for use with the field names may be defined as an alias.