MySQL in case use

Foreword: Meet such a demand, have a result, the result only records the student's score, now needs to statistic student's grade, 100-90 divides into excellent, 90-60 divides into passes, 60-0 divides into the failure. This requirement can be expressed in case statements.

Case statements are divided into simple case statements and searchable case statements.

1. The syntax for a simple case is

Case  Case_expression while   when_expression_1 then commands when when_expression_2 then   commands   ...   ELSE Commandsend

This is suitable for fixed values such as gender, 1 male, 2 female

Example: The gender of a Chinese character, 1 male, 2 female.

select*, (case sexwhen 1 Then ' Male ' when 2 Then ' female ' END) ' sex ' from ' user '

Results such as

2. The case statement can be searched, and the adaptive expression matches a different set of values.

Syntax for

When the case is    condition_1 then commands the    condition_2 then commands    ...    ELSE Commandsend

The example is the first mentioned

select*, (case is  score>=90 then ' excellent ' when score>=60 Then ' Pass ' ELSE ' failed ' END ') ' Rank ' Frommathorder by score DESC

The results are as follows

MySQL in case use