Common SQL tuning (SQL Tuning) Tips

• Establish an appropriate index (refer to "pose for proper database indexing")

• Replace or with union (for indexed columns)

• Replace in, not exist with exist, not

• Do not declare numbers in character format (invalidates the index, resulting in a full table scan)

• Do not use SELECT * (List each column after select)

• Do not perform calculations in join and WHERE clauses (the calculated values are stored in a table with a new column in advance)

• Avoid using is null and is not NULL on indexed columns

• Try to use placeholders for columns that are NULL in the table

Common SQL tuning (SQL Tuning) Tips