MySql - IF. FIELD. CASE

(DB) MySql/Null. IF. CASE.FIELD 관련

MySql - IF. FIELD. CASE

농부지기 2017. 1. 18. 14:24

[ MySql - IF. FIELD. CASE ]

1. IF 문장
 - SELECT if(emp_id=1,'X','Y') as test, emp_id from emps; 
 - SELECT IF(1>2,2,3);
 - SELECT IF(STRCMP('test','test1'),'yes','no');

2. FIELD
  - Select Name, IFNULL(ELT(FIELD(Age, 13, 14, 15, 16, 17, 18, 19)
                                    ,'Thirteen','Fourteen','Fifteen','Sixteen', 'Seventeen','Eighteen','Nineteen'), 
                      'Adult') AS AgeBracketF
      FROM Person

3. CASE
   - Select Name
       , case when Age = 13 then 'Thirteen'
 
              when Age = 14 then 'Fourteen'
 
              when Age = 15 then 'Fifteen'
 
              when Age = 16 then 'Sixteen'
 
              when Age = 17 then 'Seventeen'
 
              when Age = 18 then 'Eighteen'
 
              when Age = 19 then 'Nineteen'
 
              else 'Adult'

end as AgeBracket

FROM Person ;

3. CASE2
   - Select Name
          , CASE Age WHEN 13 then 'Thirteen' 
                     WHEN 14 then 'Fourteen' 
                     WHEN 15 then 'Fifteen' 
                     WHEN 16 then 'Sixteen'
 
                     WHEN 17 then 'Seventeen' 
                     WHEN 18 then 'Eighteen' 
                     WHEN 19 then 'Nineteen'
 
                     ELSE 'Adult' 
            END AS AgeBracket
       FROM Person ;

3. 문자열 CASE
   CASE category
        WHEN "Holiday"    THEN "Seasonal"
        WHEN "Profession" THEN "Bi_annual"
        WHEN "Literary"   THEN "Random" 
   END AS "Pattern"

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