I have a table INVENTORY which consists of inventory items. I have the following table structure:
INSTALLATION_ID
COMPONENT_ID
HISTORY_ID
ON_STOCK
LAST_CHANGE
I need to obtain the row with the max HISTORY ID for records for which the spcified LAST_CHANGE month doesn't exist.
Each COMPONENT_ID and INSTALLATION_ID can occur multiple times, they are distinguished by their respective HISTORY_ID
Example:
I have the following records
COMPONENT_ID | INSTALLATION_ID | HISTORY_ID | LAST_CHANGE
1 | 100 | 1 | 2013-01-02
1 | 100 | 2 | 2013-02-01
1 | 100 | 3 | 2013-04-09
2 | 100 | 1 | 2013-02-22
2 | 100 | 2 | 2013-03-12
2 | 100 | 3 | 2013-07-07
2 | 100 | 4 | 2013-08-11
2 | 100 | 5 | 2013-09-15
2 | 100 | 6 | 2013-09-29
3 | 100 | 1 | 2013-02-14
3 | 100 | 2 | 2013-09-23
4 | 100 | 1 | 2013-04-17
I am now trying to retrieve the rows with the max HISTORY ID for each component but ONLY for COMPONENT_IDs in which the specifiec month does not exists
I have tried the following:
SELECT
INVENTORY.COMPONENT_ID,
INVENTORY.HISTORY_ID
FROM INVENTORY
WHERE INVENTORY.HISTORY_ID = (SELECT
MAX(t2.HISTORY_ID)
FROM INVENTORY t2
WHERE NOT EXISTS
(
SELECT *
FROM INVENTORY t3
WHERE MONTH(t3.LAST_CHANGE) = 9
AND YEAR(t3.LAST_CHANGE)= 2013
AND t3.HISTORY_ID = t2.HISTORY_ID
)
)
AND INVENTORY.INSTALLATION_ID = 200
AND YEAR(INVENTORY.LAST_CHANGE) = 2013
The query seems to have correct syntax but it times out.
In this particular case, i would like to retrieve the maximum HISTORY_ID for all components except for those that have records in September.
Because I need to completely exclude rows by their month, i cannot use NOT IN, since they will just suppress the records for september but the same component could show up with another month.
Could anybody give some pointers? Thanks a lot.