I don't think that there is any "generic" approach.
Nothing usefull can be advised without knowing any sort of details.
Providing invloved table's and other objects DDLs, query itself and its current query plan could be helpful...
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"The only true wisdom is in knowing you know nothing"
"O skol'ko nam otkrytiy chudnyh prevnosit microsofta duh!":-D
(So many miracle inventions provided by MS to us...)
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