1 with fewer resources occupancy way to write sql, such as memory, cpu, IO. Through the following means
Write sql 2 less resource-intensive way;
Sql 3 prepared using the procedure more efficient way cache;
1 to avoid resource-intensive query
Avoid data type conversion
Compare the type of data the column with the column definition if not the same type, will be converted to defined types, increased CPU consumption
Instead of using EXISTS COUNT (*) to verify the presence of Data
Because you want to scan all lines
Use UNION ALL instead of UNION
To avoid the loss of data is merged
Using an index to polymerization or sort operation
Shoot well in advance of the order
Prudent use local variables in batch
Be careful of using the name of a stored procedure
Write sql 4 reduce network overhead way;
SET NOCOUNT ON <SQL queries> SET NOCOUNT OFF
The number of rows affected will not return
Write sql 5 ways to reduce query transactions consumption;
Use while the transaction will increase the consumption of the log file