hi, I'm having a bit of trouble with my SQL query. It takes about 26h to run on a 3Ghz PC. I'd really like to speed this up.
I put this query in a loop to iterate over 20 tables (each table including summary has 400k records), each time the table name changes. I this case it's m_alal. Each table has an identical primary key ECP_TAG but the RATING column is different. What I doing is: Classifying RATING has High, Moderate, Low No Data or Nill. Then counting how many tables classify the PK in one of these categories. This result is kept in my summary table. I end up with a summary table like: ECP_CODE | HIGH | MODERATE | LOW ... M3456 | 3 | 4 | 7 .. Because I have 20 tables, if you were to add up along each row it would sum up to 20. Anyone have some suggestion on speeding this up. update public.summary set "MAX_VAL" = CASE WHEN public.m_alal."RATING" > public.summary."MAX_VAL" THEN public.m_alal."RATING" ELSE public.summary."MAX_VAL" END, "MIN_VAL" = CASE WHEN public.m_alal."RATING" < public.summary."MIN_VAL" THEN public.m_alal."RATING" ELSE public.summary."MIN_VAL" END, "NO_DATA" = CASE WHEN public.m_alal."RATING" = 0 THEN public.summary."NO_DATA" + 1 END, "NILL" = CASE WHEN public.m_alal."RATING" = -1 THEN public.summary."NILL" + 1 ELSE public.summary."NILL" END, "HIGH" = CASE WHEN public.m_alal."RATING" > 75 THEN public.summary."HIGH" + 1 ELSE public.summary."HIGH" END, "MODERATE" = CASE WHEN public.m_alal."RATING" > 30 THEN public.summary."MODERATE" + 1 ELSE public.summary."MODERATE" END, "LOW" = CASE WHEN public.m_alal."RATING" < 25 THEN public.summary."LOW" + 1 ELSE public.summary."LOW" END FROM public.m_alal WHERE public.summary."ECP_TAG" = public.m_alal."ECP_TAG" AND public.m_alal."RATING" IS NOT NULL; ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend