Query Spatial Data for Nearest Neighbor

database in Microsoft Fabric

A common query used with spatial data is the nearest neighbor query. Nearest neighbor

queries are used to find the closest spatial objects to a specific spatial object. For example, a

store locator for a web site often must find the closest store locations to a customer location.

A nearest neighbor query can be written in various valid query formats, but for the nearest

neighbor query to use a spatial index the following syntax must be used.

In SQL Server,

and

clauses are used to perform a nearest neighbor query on

spatial data columns. The

clause contains a call to the

method for the

spatial column data type. The

clause indicates the number of objects to return for the

query.

TOP
ORDER BY
ORDER BY
STDistance()
TOP
SELECT
TOP ( number )
[
WITH
TIES
]
[ * | expression ]
[,.]
FROM spatial_table_reference,.
[
WITH (
[
INDEX ( index_ref ) ]
[ ,
SPATIAL
_
WINDOW
_
MAX
_
CELLS
=
<value>
]
[ ,. ]
)
]
WHERE column_ref.
STD istance ( @spatial_ object )
{
[
IS
NOT
NULL
] | [
< const ] | [ >
const ]
| [
<= const ] | [ >
= const ] | [
<>
const ] ]
}
[
AND
{ other_predicate } ]
}
ORDER
BY column_ref.
STD istance ( @spatial_ object ) [ ,.n ]
[ ; ]