Question

This is the select statement which i have got the correct answer:

select s_billing_cycle.Billing_cycle from s_billing_cycle 
join o_daily_lcsgeneration_copy on o_daily_lcsgeneration_copy.Location=s_billing_cycle.Location where o_daily_lcsgeneration_copy.Date between s_billing_cycle.From_Date and s_billing_cycle.To_Date

while updating the same query into another table i couldnt do that using update query getting :
You cant update target table “o_daily_lcsgeneration_copy” for update in FROM Clause
the query i have used is :

update o_daily_lcsgeneration_copy  set o_daily_lcsgeneration_copy.Billing_cycle = (select s_billing_cycle.Billing_cycle from s_billing_cycle join o_daily_lcsgeneration_copy on o_daily_lcsgeneration_copy.Location=s_billing_cycle.Location where o_daily_lcsgeneration_copy.Date between s_billing_cycle.From_Date and s_billing_cycle.To_Date) 

Help me !!!

Answer 1

wrap it in a subquery (thus creating temporary table)

UPDATE  o_daily_lcsgeneration_copy
SET     o_daily_lcsgeneration_copy.Billing_cycle = 
(
    SELECT Billing_cycle
    FROM
    (
        SELECT  s_billing_cycle.Billing_cycle
        FROM    s_billing_cycle
                INNER JOIN o_daily_lcsgeneration_copy
                    ON o_daily_lcsgeneration_copy.Location = s_billing_cycle.Location
        WHERE   o_daily_lcsgeneration_copy.DATE BETWEEN s_billing_cycle.From_Date
                AND s_billing_cycle.To_Date
    ) s
)

or JOIN the tables

UPDATE  o_daily_lcsgeneration_copy a
        INNER JOIN s_billing_cycle b
            ON a.Location = b.Location
SET     a.Billing_cycle = b.Billing_cycle
WHERE   a.DATE BETWEEN b.From_Date AND b.To_Date