SQL statement query latitude and longitude range

Specifies a latitude and longitude, given a range value (in kilometers), to isolate the data within this range around the latitude and longitude.
Longitude: 113.914619
Latitude: 22.50128
Range: 2km
Longitude as a data table longitude field
Latitude for the data table latitude field

SQL is tested under MySQL, other databases may need to be modified

The SQL statement is as follows: SELECT * from location where sqrt (

(

((113.914619-longitude) *pi () *12656*cos (((22.50128+latitude)/2) *pi ()/ +/+)

*

((113.914619-longitude) *pi () *12656*cos (((22.50128+latitude)/2) *pi ()/ +/+)

)

+

(

((22.50128-latitude) *pi () *12656/)

*

((22.50128-latitude) *pi () *12656/)

)

) <2&NBSP;&NBSP;