SQL-92 La requête pour trouver la première date dépend de la modification de la valeur de la colonne

Question

J'interroge un système de données avec une interface OLEDB qui prend en charge SQL92. Mon problème de requête est équivalent à celui résolu ici: SQL Query to find earliest date dependent on column value changing, mais la solution fournie là et copié ci-dessous est trop avancée pour SQL92:

SELECT JobCodeId, MIN(LastEffectiveDate) AS mindate 
FROM ( 
     SELECT *, 
       prn - rn AS diff 
     FROM ( 
       SELECT *, 
         ROW_NUMBER() OVER (PARTITION BY JobCodeID 
            ORDER BY LastEffectiveDate) AS prn, 
         ROW_NUMBER() OVER (ORDER BY LastEffectiveDate) AS rn 
       FROM @tmp 
       ) q 
     ) q2 
GROUP BY 
     JobCodeId, diff 
ORDER BY 
     mindate 

Que serait une version compatible SQL92 de cette solution ressembler?

Answer 1

Utilisation:

SELECT JobCodeId, 
     MIN(LastEffectiveDate) AS mindate 
    FROM (SELECT *, 
       prn - rn AS diff 
      FROM (SELECT *, 
         (SELECT CASE WHEN COUNT(*) = 0 THEN 1 ELSE COUNT(*) END 
          FROM @tmp t 
          WHERE t.JobCodeID = r.JobCodeID 
          AND t.LastEffectiveDate <= x.LastEffectiveDate) AS prn, 
         (SELECT COUNT(*) + 1 
          FROM @tmp t 
          WHERE t.LastEffectiveDate <= x.LastEffectiveDate) AS rn 
        FROM @tmp x) q 
     ) q2 
GROUP BY JobCodeId, diff 
ORDER BY mindate