reduce function for couch

map_reduce_timespans.js

{
   "_id": "_design/num_ar_id",
   "_rev": "36-145879462ded07757a29757bb5b5b92b",
   "language": "javascript",
   "views": {
       "count_of_ar_id": {
           "map": "function(doc) {\n  if (doc.ar_id) {\n    emit(doc.ad_id, doc.ar_id );\n  }\n}",
           "reduce": "function(keys, values, rereduce) {\n  if (rereduce) {\n    return sum(values);\n  }\n  else {\n    return values.length;\n  }\n}"
       },
       "count_of_ar_id_impl": {
           "map": "function(doc) {\n  if (doc.ar_id && doc.subject_id && doc.ad_id) {\n    emit([doc.subject_id, doc.ad_id, doc.ar_id, doc.url], doc.ar_id );\n  }\n}",
           "reduce": "_count"
       },
       "select_ar_id": {
           "map": "// map\nfunction(doc) {\n  if (doc.ar_id) {\n    emit(doc.ar_id, null);\n  }\n}"
       },
       "sum_values_ar_id": {
           "map": "function(doc) {\n  emit(ar_id, 1);\n}",
           "reduce": "function(keys, values) {\n   return sum(values);\n}"
       },
       "select_subject_id": {
           "map": "// map\nfunction(doc) {\n  if (doc.subject_id) {\n    emit(doc.subject_id, doc);\n  }\n}"
       }
   },
   "lists": {
       "simple": "function(head, req) {var row; send(\"begin\");\n while(row = getRow()) {\n    send(row.value);\n    send(row.key);\n  }\n  send(\"end\");\n}",
       "csv": "function(head, req) {var row;  while(row = getRow()){send(row.key);send(',');send(row.value);send('\\n');}send('\\n');send('\\n');send('END');}",
       "export-ar_ids": "function(head, req)  { \n var row\n var rows=[]\n while(row = getRow()) { \n rows.push(row) \n } \n rows.sort(function(a,b) { \n return b.value-a.value\n }) \n send(JSON.stringify({\"rows\" : rows}))\n}"
   }
}