Re: Adding index kills query

[Robert Stafford]

Here are the explain results using indexes:

explain select iCompanyID, sum(fPurchaseAmt) FROM Trans_smp GROUP BY iCompanyID;

id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Trans_smp index NULL idxComp 9 NULL 15272017

And ignoring indexes:

explain
select iCompanyID, sum(fPurchaseAmt)
FROM Trans_smp
ignore index (idxCompBrand)
ignore index (idxComp)
ignore index (idxCompPurchAmt)
GROUP BY iCompanyID
;

id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Trans_smp ALL NULL NULL NULL NULL 15272017 Using temporary; Using filesort