MySql中判斷字符串相等

MySql中判斷字符串相等

參考博客：https://blog.csdn.net/yangfengjueqi/article/details/72821603

教程：https://www.runoob.com/mysql/mysql-operator.html

項目案例：V1--->V3實現過程。
 

    SELECT

          b.issue_id,
          b.current_version,
          b.customer_cloud_name,
          b.gmt_actual_resolve,
          b.gmt_expect_resolve,
          b.gmt_issue_feedback,
          b.gmt_modified,
          b.issue_create_person,
          b.issue_duty_person,
					b2.sended_timout_ding,
          b.issue_feedback_person,
          b.issue_name,
          b.issue_no,
          b.issue_present_person,
          b.issue_priority,
          b.issue_status,
          b.major_catagory,
          b.rel_project ,


          b2.aone_url,
          b2.cost_impact_level,
          b2.deliver_stage,
          b2.functional_impact_level,
          b2.is_analyse,
          b2.is_firmware,
          b2.question_party,
          b2.submit_aone,
          b2.submit_work_order,
          b2.work_order_url,
          b2.now_look_person,

        b2.gmt_allocation,
        b2.gmt_deliver,
        b2.gmt_to_sovling,

          c.subproject_id,    c.subproject_name


    FROM  issue_detail b
    INNER JOIN deliver_question b2 ON b.issue_id = b2.issue_id
    INNER JOIN deliver_subproject c ON b2.subproject_id = c.subproject_id
    WHERE
/*優先級 :  緊急1：15分鐘；  高2：1小時； 中3：3小時 ；   問題分配時間 和  到當前時間  間隔。 */
CASE
    when b.issue_priority =1 then timestampdiff(MINUTE,b2.gmt_allocation,NOW())  > 15
    when b.issue_priority =2 then timestampdiff(MINUTE,b2.gmt_allocation,NOW())  > 60
    when b.issue_priority =3 then timestampdiff(MINUTE,b2.gmt_allocation,NOW())  > 180
END
   and b.is_valid=1
    AND b2.is_valid=1
    AND c.is_valid=1
and b.issue_duty_person like '%[%'  /* 值班人不爲空 */
AND b.issue_status = '1'  /* 處理中 */
AND b2.gmt_allocation IS NOT NULL  /* 分配時間不爲空 */

 /* ---------------V3新增條件，發送過通知： <=>  和 = 效果不同，<=>可以嚴格比較null，=不能比較有null情況  。---ok  */
 and !(b.issue_duty_person <=> b2.sended_timout_ding)



 /* ---------------V2新增條件，發送過通知： <> 和 != 效果相同,都不能比較有null情況  ----不行  */
 and b.issue_duty_person <> b2.sended_timout_ding
 
 
 /* ---------------V1新增條件，發送過通知： like 方式 取非---ok， 但是不嚴謹，而且語法繁瑣  */
and b.issue_id NOT IN (
    SELECT
b.issue_id
    FROM  issue_detail b
    INNER JOIN deliver_question b2 ON b.issue_id = b2.issue_id
    INNER JOIN deliver_subproject c ON b2.subproject_id = c.subproject_id
    WHERE
/*優先級 :  緊急1：15分鐘；  高2：1小時； 中3：3小時 ；   問題分配時間 和  到當前時間  間隔。 */
CASE
    when b.issue_priority =1 then timestampdiff(MINUTE,b2.gmt_allocation,NOW())  > 15
    when b.issue_priority =2 then timestampdiff(MINUTE,b2.gmt_allocation,NOW())  > 60
    when b.issue_priority =3 then timestampdiff(MINUTE,b2.gmt_allocation,NOW())  > 180
END
   and b.is_valid=1
    AND b2.is_valid=1
    AND c.is_valid=1
and b.issue_duty_person like '%[%'  /* 值班人不爲空 */
AND b.issue_status = '1'  /* 處理中 */
AND b2.gmt_allocation IS NOT NULL  /* 分配時間不爲空 */
and  b.issue_duty_person LIKE CONCAT('%',b2.sended_timout_ding, '%' )    /* 新增條件： 發送過通知 */
)