Answer Posted / rajnish chauhan

Follow the steps for performance SQL Tunning.
1) First of all tables structure should be in normalization form.
2) Then Index and tables Statistics should be upto date.
3) make it different tables table space for tables and index.
4) Avoid unnecessary joins from the query.
5) Avoid Full Table Scan and Index Skip scan.if query fetching less then 15% records from the table then index scan faster then FTS.and FTS is better then index scan if tables consist larg no of data because Index scan read multiple time on each row where as FTS read single time for each row.
6)monitor Plan through Explain plan or TKPROFF.
7)Table ordering also improve the performance of the query like.Master table should take first place then after Transaction table.
8) Check index path used or not in explain plan .if not then check weather index enable or not.then use Index Hint to forcefully used.
9)Avoid function on index column.
10) other small things you can apply like use Having instead of Where clause , use Exists then IN , use Substring instead of <> caluse.

Thanks

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