sql oracle-筛选查询sql时使用大小写

我有以下疑问

select
    ens.ID_ENS,
    ens.NOM_ENS,
    
   -- for the first SURVEILLANT
    disp.SALLE_EXAM,
    disp.NB_HEURES_ENS,

    -- for the second SURVEILLANT
    disp.SALLE_EXAM2,
    disp.NB_HEURES_ENS2

from ESP_ENSEIGNANT ens, ESP_MODULE_PANIER_CLASSE_SAISO disp
WHERE ens.ID_ENS IN (disp.SURVEILLANT, disp.SURVEILLANT2) AND ens.NOM_ENS != 'A AFFECTER';

我想更新显示SALLE_考试的查询，请注意，仅用于监督

select
    ens.ID_ENS,
    ens.NOM_ENS,

    CASE
        WHEN ens.ID_ENS = disp.SURVEILLANT THEN (disp.SALLE_EXAM AS "EXAM", disp.NB_HEURES_ENS AS "HOURDISP")
        WHEN ens.ID_ENS = disp.SURVEILLANT2 THEN (disp.SALLE_EXAM2 AS "EXAM", disp.NB_HEURES_ENS2 AS "HOURDISP")
    END

from ESP_ENSEIGNANT ens, ESP_MODULE_PANIER_CLASSE_SAISO disp
WHERE ens.ID_ENS IN (disp.SURVEILLANT, disp.SURVEILLANT2) AND ens.NOM_ENS != 'A AFFECTER';

---

您可以使用显式的

JOIN

语法重写查询，如下所示

SELECT ens.ID_ENS,
       ens.NOM_ENS,      
       CASE
         WHEN ens.ID_ENS = disp.SURVEILLANT THEN
           disp.SALLE_EXAM 
         WHEN ens.ID_ENS = disp.SURVEILLANT2 THEN
           disp.SALLE_EXAM2
       END AS "EXAM",
       CASE
         WHEN ens.ID_ENS = disp.SURVEILLANT THEN
          disp.NB_HEURES_ENS 
         WHEN ens.ID_ENS = disp.SURVEILLANT2 THEN
          disp.NB_HEURES_ENS2
       END AS "HOURDISP"
  FROM ESP_ENSEIGNANT ens
  JOIN ESP_MODULE_PANIER_CLASSE_SAISO disp
    ON ens.ID_ENS IN (disp.SURVEILLANT, disp.SURVEILLANT2)
   AND ens.NOM_ENS != 'A AFFECTER';

---

旁注：如果

disp.SURVEILLANT

和

disp.SURVEILLANT2

的值相等，则将分别选择

disp.SALLE\u考试

和

disp.NB\u HEURES

。例如，第一个组件具有优先权。

请提供样本数据和所需结果。为什么不使用正确、明确、标准、可读的

JOIN

语法？