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Joins Optimization In SQL server

 

What are Joins In SQL ?

Joins are command used to combine two or more dataset, horizontally. The dataset may have a relationship between them or not, still joins work. If primary key and foreign key relationship exist then the output result is under refrential integrity and ine can rely on final output. Otherwise the final joined output is not reliable.

JOINS Optimization:

1) always choose inner and outer join wisely, inner join result less rows then outer joins in most cases, so it also results faster.

2) use of join hint i.e. Merge, Nested or Hash should be used wisely, for coming to an conclusive execution plan.

3) use of index on the column in where clause as well as the column on which joins are performed is again improving performance.

4) writing joins with nolock hint is better approach.

5) updating statistics of the tables, before running joins queries is better approach.

These are the some common practices one can used, beyond that SQL profiler Is always a better option to optimize one query.

Please post queries in the comments. Thankyou 


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