use of case ... when ... end ...

use of case ... when ... end ...

Requirements: When checking the database, if the shareholder_type field is 1, the output type is enterprise, and the shareholder_type field is 2, then the output type is personal, otherwise output

 SELECT shareholder_name AS name,proportion AS category,
        (CASE
        WHEN shareholder_type = '1' THEN '企业'
        WHEN shareholder_type = '2' THEN '个人'
        ELSE '其他' END ) AS type
      FROM
      d_ownership_overview
      WHERE 1=1
      <if test="enterpriseName != null and enterpriseName != ''">
          AND enterprise_name = #{enterpriseName}
      </if>

Simple Case function, more concise

Output male when sex is 1, output female when it is 2, otherwise output
CASE sex
WHEN '1' THEN 'Male'
WHEN '2' THEN 'Female'
ELSE 'Other' END

Case search function, more flexible

CASE WHEN sex = ‘1’ THEN ‘男’
WHEN sex = ‘2’ THEN ‘女’
ELSE ‘其他’ END

Note: (It has nothing to do with the above)
nohup.out is the monitoring log file on the server
tail -1000 nohup.out (view the last 1000 lines of log text)
tail -f nohup.out (monitoring log printing)