Common SQL tuning (SQL Tuning) Tips

Source: Internet
Author: User

  • 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

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