Quantifiers

Example 3. Quantifier Pushdown

XQuery

for $u in collection("USERS")/USERS
where every $h in collection("HOLDINGS")/HOLDINGS[USERID=$u/USERID]
satisfies $h/SHARES > 1000
return <user id="{$u/LASTNAME}"/>

Generated SQL

SELECT ALL
  nrm5."LASTNAME" AS RACOL2
FROM
  "PEPPINO"."USERS" nrm5
WHERE
  NOT EXISTS(
        SELECT ALL 1 AS RACOL1
          FROM "PEPPINO"."HOLDINGS" nrm10
         WHERE  CASE WHEN nrm10."SHARES" > 1000 THEN 0 ELSE 1 END) !=0
           AND nrm10."USERID" = nrm5."USERID"
           AND LENGTH(nrm10."USERID") = LENGTH(nrm5."USERID")