Otherwise, try something like this:
SELECT "Rut Cliente"
FROM "Internet_Abril"
WHERE "Rut Cliente" NOT IN (SELECT "Rut Cliente" FROM
"Internet_Enero")
AND "Rut Cliente" NOT IN (SELECT "Rut Cliente" FROM
"Internet_Febrero")
AND "Rut Cliente" NOT IN (SELECT "Rut Cliente" FROM
"Internet_Marzo");
You could also compare the performance of that to this and choose the one that works the best:
SELECT "Rut Cliente"
FROM "Internet_Abril" a
LEFT JOIN "Internet_Enero" e ON a."Rut Cliente" = e."Rut Cliente"
LEFT JOIN "Internet_Febrero" f ON a."Rut Cliente" = f."Rut Cliente"
LEFT JOIN "Internet_Marzo" m ON a."Rut Cliente" = m."Rut Cliente"
WHERE e."Rut Cliente" IS NULL AND f."Rut Cliente" IS NULL and m."Rut Cliente" IS NULL;
Meetesh
On 9/7/05, Christian Compagnon <[EMAIL PROTECTED]> wrote:
Hello,
I'm a newbie in postgresql, I've installed it on a Windows XP machine
( I can't use linux, it's a company machine ), I'm courious why this
query takes so long
SELECT "Rut Cliente"
FROM "Internet_Abril"
WHERE "Rut Cliente" NOT IN ((SELECT "Rut Cliente" FROM
"Internet_Enero") UNION (SELECT "Rut Cliente" FROM
"Internet_Febrero") UNION (SELECT "Rut Cliente" FROM
"Internet_Marzo"));
it takes about 100 minutes to complete the query.
All tables has index created ( Rut Cliente is a VarChar ), and tables
has 50.000 records each.
The explain for the query tells the following
"QUERY PLAN
Seq Scan on "Internet_Abril" (cost=19406.67..62126112.70 rows=24731 width=13)
Filter: (NOT (subplan))
SubPlan
-> Materialize (cost=19406.67..21576.07 rows=136740 width=13)
-> Unique (cost=17784.23..18467.93 rows=136740 width=13)
-> Sort (cost=17784.23..18126.08 rows=136740 width=13)
Sort
Key: "Rut Cliente"
-> Append (cost=0.00..3741.80 rows=136740 width=13)
-> Subquery Scan "*SELECT* 1" (cost=0.00..1233.38
rows=45069 width=13)
-> Seq Scan on "Internet_Enero" (cost=0.00..782.69
rows=45069 width=13)
-> Subquery Scan "*SELECT* 2" (cost=0.00..1104.06
rows=40353 width=13)
-> Seq Scan on "Internet_Febrero" (cost=0.00..700.53
rows=40353 width=13)
-> Subquery Scan "*SELECT* 3" (cost=0.00..1404.36
rows=51318 width=13)
-> Seq Scan on "Internet_Marzo" (cost=0.00..891.18
rows=51318 width=13)
Any help will be apreciated, It's for my thesis
saludos
Christian
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