一、查詢序列的下一值

(select decode(max(RECORD_VOLTAGE_ID),null,0,max(RECORD_VOLTAGE_ID)+1) RECORD_VOLTAGE_ID from RECODR_MAINTAIN_VOLTAGE)

二、排序置前

 select * from tb order by decode(blogid,3,1,2), blogid;

BLOGID值為3的那條記錄被轉換為了1，而其他的記錄都是2。

有時候我們需要根據條件來進行統計:

三、通過decode判斷並生成設定類別列，

不用再資料庫中多增加類別欄位

select us.*
          from (SELECT u.*,
                       decode(me.member_id, NULL, 0, 1) AS IS_TRUE,
                       decode(jo.join_id, NULL, 0, 1) AS IS_JOIN
                  FROM CT_USER u
                  LEFT JOIN member me
                    ON u.user_id = me.id
                  LEFT JOIN pb_join jo
                    ON u.user_id = jo.id ) us
 

四、設定識別符號

oracle decode統計關聯表是否有資料

(select a.emer_id,
       a.CHECK_METHOD,
       a.IS_CLOSED,
       (select decode(count(*), 0, '0', '1')
          from GL_EMER e
         where e.emer_id = a.emergency_id) as CHECK_STATUS
  from GL_EMERGENCY a)b

五、decode進行統計運算

 create or replace view v_wjx_hz as
select "TERRITORIALITYUNIT","YEAR","MONTH","WORKID","DEVICE_ID","DEVICE_NAME","DEVICE_LOCNO","DEV_CLASS_ID","DEVICE_PRESSURE_LEVEL","T_JXZS","T_JTDX","T_ZXXX","T_TS","T_GHFT","T_GHPM","T_FKD","T_OXH","T_ZHQPT","G_JXZS","G_KG","G_PW","G_Z","G_BZ","G_GHLXS","G_GHOXH","F_FMWH","F_FMBWH","F_CLWH","F_CLBWH","F_QNJZQXY","F_QNJZRHY","F_QNJZMFZ" from
(
select t1.territorialityunit,
       t1.year,
       t1.month,
       t1.workid,
       t1.device_id,
       t1.device_name,
       t1.device_locno,
       t1.dev_class_id,
       t1.device_pressure_level,
       t2.t_jxzs,
       t2.t_jtdx,
       t2.t_zxxx,
       t2.t_ts,
       t2.t_ghft,
       t2.t_ghpm,
       t2.t_fkd,
       t2.t_oxh,
       t2.t_zhqpt,
       t3.g_jxzs,
       t3.g_kg,
       t3.g_pw,
       t3.g_z,
       t3.g_bz,
       t3.g_ghlxs,
       t3.g_ghoxh,
       t4.f_fmwh,
       t4.f_fmbwh,
       t4.f_clwh,
       t4.f_clbwh,
       t4.f_qnjzqxy,
       t4.f_qnjzrhy,
       t4.f_qnjzmfz
  from eam_wjx_result_tb t1
  left join (select  decode(t_jtdx,null,0,t_jtdx)+decode(t_zxxx,null,0,t_zxxx)+decode(t_ts,null,0,t_ts) as t_jxzs, t5.* from (select workid,
                    sum(case jxfs
                          when '1' then
                           1
                        end) as t_jtdx,
                    sum(case jxfs
                          when '2' then
                           1
                        end) as t_zxxx,
                    sum(case jxfs
                          when '3' then
                           1
                        end) as t_ts,
                    sum(ghft) as t_ghft,
                    sum(ghpm) as t_ghpm,
                    sum(fkd) as t_fkd,
                    sum(oxh) as t_oxh,
                    sum(zhqpt) as t_zhqpt
               from eam_wjx_result_tyq_tb
              group by workid) t5) t2
    on t1.workid = t2.workid
  left join (select decode(g_kg,null,0,g_kg)+decode(g_pw,null,0,g_pw) as g_jxzs, t6.* from (select workid,
                    sum(case jxfs
                          when '1' then
                           1
                        end) as g_kg,
                    sum(case jxfs
                          when '2' then
                           1
                        end) as g_pw,
                    sum(case lxsfz
                          when '3' then
                           1
                        end) as g_z,
                    sum(case lxsfz
                          when '4' then
                           1
                        end) as g_bz,
                    sum(ghlxs) as g_ghlxs,
                    sum(ghoxh) as g_ghoxh
               from eam_wjx_result_glq_tb
              group by workid) t6) t3
    on t1.workid = t3.workid
  left join (select workid,
                    sum(case fmsfwh
                          when '1' then
                           1
                        end) as f_fmwh,
                    sum(case fmsfwh
                          when '0' then
                           1
                        end) as f_fmbwh,
                    sum(case clxsfwh
                          when '1' then
                           1
                        end) as f_clwh,
                    sum(case clxsfwh
                          when '0' then
                           1
                        end) as f_clbwh,
                    sum(qnjzqxy) as f_qnjzqxy,
                    sum(qnjzrhy) as f_qnjzrhy,
                    sum(qnjzmfz) as f_qnjzmfz
               from eam_wjx_result_fm_tb
              group by workid) t4
    on t1.workid = t4.workid
union all
select '合計' territorialityunit,
       null year,
       month,
       null workid,
      null device_id,
      null device_name,
       null device_locno,
     null dev_class_id,
       null device_pressure_level,
       sum(t2.t_jxzs),
       sum(t2.t_jtdx),
        sum(t2.t_zxxx),
        sum(t2.t_ts),
        sum(t2.t_ghft),
       sum( t2.t_ghpm),
        sum(t2.t_fkd),
        sum(t2.t_oxh),
       sum( t2.t_zhqpt),
       sum( t3.g_jxzs),
       sum( t3.g_kg),
...
 

統計不同類別的人數

select sum(p.total) total,sum(p.Committee) Committee,sum(p.general) general,sum(p.branch) branch,sum(p.pmgroup) pmgroup from (select t.ORG_NAME as orgName,
       t.org_id as OrgId,
       count(t.party_org_id) as total,
       count(DECODE(t.ORG_TYPE, '1', 1)) as partyCommittee,
       count(DECODE(t.ORG_TYPE, '2', 1)) as generalBranch,
       count(DECODE(t.ORG_TYPE, '3', 1)) as branch,
       count(DECODE(t.ORG_TYPE, '4', 1)) as pmgroup
  from pb_party_org t
 inner join (SELECT *
               FROM pb_org
              START WITH party_org_id in ('10')
             CONNECT BY nocycle PRIOR org_id = last_org) po
    on t.org_id = po.org_id
 group by t.ORG_NAME, t.org_id) p