Introduction - If you have any usage issues, please Google them yourself
people in the use of SQL often fall into the trap, that is too focused on the findings is correct, and ignore a different method may exist between the performance differences, these differences in large or complex database environment (such as online transaction processing or decision support OLTP system DSS) has become even more obvious. In practice I found that the poor tend to SQL from inappropriate design of the index, not fully connected and non-optimal conditions where the phrase. On their proper optimization, and their operating speed has been improved! Now I will be three aspects of this summary :