Question

我有一个规划应用程序的表，我试图将最近的5个应用程序返回给一个属性，通过Postgres查询通过最接近最远距离的顺序排序，通过PHP作为JSON数组返回。

结果已成功返回，但似乎没有正确排序。起初我以为是因为ST_Distance的结果值是浮动的，所以将它们转换为整数，但它们仍然不会按距离返回记录。

这个SQL中有什么明显的错误吗？

// Search the database for all similar items
    $sql = pg_query($conn, "SELECT DISTINCT b.reference, b.application_number, b.site_address, b.proposal, cast((st_distance(a.geom, b.geom)) as integer) as dist FROM addresses.llpg_standard a, planning.planning_applications_current b WHERE a.uprn = $query ORDER BY dist ASC LIMIT 5");
    $array = array();

我的结果查询结果如下，您可以看到'dist'值不按顺序...

[
  {
    "reference": "228028",
    "application_number": "RU.17\/1320",
    "site_address": "64 The Avenue\r\nEgham\r\nTW20 9AD",
    "proposal": "Application seeking approval of details pursuant to condiitions 2 (Materials), 3 (Surfacing Materials), 4 (Tree Portection), 10 (Construction Transport Management Plan), 12 (Travel Plan), 13 (Construction Management Plan), 21 (Gas Prroof Membrane), 23 (Archaeology), (24( Flood Risk Management Plan), 28 (CEMP) of planning permission RU.16\/1453 (80 bed Care Home, Ancillary facilities and retention of 64 The Avenue).",
    "dist": "120"
  },
  {
    "reference": "228568",
    "application_number": "RU.17\/1303",
    "site_address": "64 The Avenue\r\nEGHAM\r\nTW20 9AD",
    "proposal": "Proposed three storey 80 bed care home with ancillary facilities in the roof space.",
    "dist": "120"
  },
  {
    "reference": "233449",
    "application_number": "RU.17\/1820",
    "site_address": "Egham Leisure Centre\r\nVicarage Road\r\nEGHAM\r\nTW20 8NL",
    "proposal": "Variation of conditions 2 (approved plans), 5 ( Sustainable Drainage Plan) and 29 ( Flood Risk Assessment) of RU.17\/0488",
    "dist": "280"
  },
  {
    "reference": "236908",
    "application_number": "RU.18\/0089",
    "site_address": "Egham Leisure Centre\r\nVicarage Road\r\nEGHAM\r\nTW20 8NL",
    "proposal": "Details pursuant to Condition 28 (Replacement Temporary Bin Storage) of planning permission RU.17\/0488 (Demolition of existing leisure centre and erection of replacement leisure centre (Use Class D2); with 1no. outdoor synthetic sports pitch with associated fencing and lighting columns; new service access off Vicarage Road; alterations to the existing car park including overflow area; landscaping and public realm works; installation of a substation; and associated works). ",
    "dist": "280"
  },
  {
    "reference": "239748",
    "application_number": "RU.18\/0388",
    "site_address": "1 Vicarage Crescent\r\nEGHAM\r\nTW20 9JP",
    "proposal": "Proposed lawful development Certificate to establish whether planning permission is required for a rear extension",
    "dist": "18"
  }
]

Answer 1

如果您能负担得起直接从数据库中检索JSON：

基于以下表格结构...

CREATE TEMPORARY TABLE tmp_geo (id SERIAL, geom GEOMETRY);

...包含以下记录......

id |            geom            
----+----------------------------
  1 | POINT(14.0025 51.056388)
  2 | POINT(14.57249 52.04263)
  3 | POINT(10.7809 51.983199)
  4 | POINT(14.114722 51.067777)
  5 | POINT(14.14779 51.28735)
  6 | POINT(10.546666 51.506111)
  7 | POINT(14.650439 51.88293)
  8 | POINT(9.82623 48.215339)
  9 | POINT(14.408049 52.700519)
 10 | POINT(8.47574 51.023049)

...使用以下SQL查询...

SELECT row_to_json(j)
FROM (
   SELECT id,CAST(ST_Distance(ST_GeomFromText('POINT(50.12 8.69)',4326),geom) AS INTEGER) AS dist
   FROM tmp_geo
   ORDER BY dist ASC
) j;

...您可以获得完美排序的JSON输出：

     row_to_json     
---------------------
 {"id":4,"dist":56}
 {"id":7,"dist":56}
 {"id":2,"dist":56}
 {"id":8,"dist":56}
 {"id":5,"dist":56}
 {"id":1,"dist":56}
 {"id":9,"dist":57}
 {"id":6,"dist":58}
 {"id":3,"dist":58}
 {"id":10,"dist":59}

Answer 2

我意识到问题出在随后的一些代码中，我在获取数据后对其进行了排序。

由于它已经被排序，我只是删除了它，现在它正确排序。

PostGIS按ST_Distance排序 - 不按距离排序记录

2 个答案: