MySQL in query optimization

November 29, 2014 21:01:01

Scenario: Sometimes there are very many discontinuous values in the select in statement that query the database, which can affect query efficiency

Method: Convert a select in query into multiple select between and statements

Code: Core code (ID to sort order)

1      Public functionGroup()2     {3         //$a = array (1,2,3,5,7,8,9);4         $a=Array(1,3,4,5,7,8,9);5         $len=Count($a);6         $cur= 0;//subscript of the currently traversed element7         $pre=$a[0]; The value of the previous element8 9         $new=Array(' 0 ' + =Array($a[0]));Ten          for($i= 1;$i<$len;$i++) { One             if(($a[$i] -$pre) = = 1 ) { A                 $new[$cur][] =$a[$i]; -}Else { -                 $cur=$i; the                 $new[$cur][] =$a[$i]; -             } -             $pre=$a[$i]; -         } +  -         Print_r($new); +}

Results

1 Array2 (3[0] = =Array4         (5[0] = 16         )7 8[1] = =Array9         (Ten[0] = 3 One[1] = 4 A[2] = 5 -         ) -  the[4] = =Array -         ( -[0] = 7 -[1] = 8 +[2] = 9 -         ) +  A)

MySQL in query optimization