加快查询执行

Question

I have table with millions of record from am extracting some thousands of rows to temp table even if query on temp table with simple where it is taking hours to get me the result , does any know how i can speed up query processing time??

Query is something like this

 Select col_name col1, col_name2 col2 from tbl_temp where col_name3 = 'value' and
 col_name4 = 'value' order by col_name desc limit 2; 

Answer 1

确保col_name3，col_name4和col_name具有正确的索引编制，并在可能的情况下，按日期进行分区

Answer 2

如果尚未将索引添加到临时表，则应该这样做。

Answer 3

Try explain ing the query. It will give you lots of information about how the query is executed, including how many rows it has to go through and whether or not it can use indexes.

EXPLAIN Select col_name col1, col_name2 col2 from tbl_temp where col_name3 = 'value' and col_name4 = 'value' order by col_name desc limit 2;