refactor : chart gets new querying way steppair

README.md

@@ -441,7 +441,7 @@ response body
 
 Chart API returns distribution of a numeric column in a table
 
-It comes in **SIX** powerful flavours
+It comes in **SEVEN** powerful flavours
 
 1. Chart : With min, max, step in query params :fire::fire:
 [:arrow_heading_up:](#api-overview)
@@ -514,7 +514,25 @@ Response
 
 ```
 
-3. Chart : with no params :fire::fire:
+3. Chart : With step paits in params :fire::fire:
+[:arrow_heading_up:](#api-overview)
+
+This API returns distribution between each step pair
+
+```
+/api/payments/chart?_fields=amount&steppair=0,50000,40000,100000
+
+Response
+
+[
+    {"amount":"0 to 50000","_count":231},
+    {"amount":"40000 to 100000","_count":80}
+]
+
+
+```
+
+4. Chart : with no params :fire::fire:
 [:arrow_heading_up:](#api-overview)
 
 This API figures out even distribution of a numeric column in table and returns the data
@@ -556,7 +574,7 @@ Response
 
 ```
 
-4. Chart : range, min, max, step in query params :fire::fire:
+5. Chart : range, min, max, step in query params :fire::fire:
  [:arrow_heading_up:](#api-overview)
  
  This API returns the number of rows where amount is between (0,25000), (0,50000) ... (0,maxValue)
@@ -593,7 +611,7 @@ Response
  
  ```
 
-5. Range can be specified with step array like below
+6. Range can be specified with step array like below
 
  ```
 /api/payments/chart?_fields=amount&steparray=0,10000,20000,70000,140000&range=1
@@ -618,7 +636,7 @@ Response
 ]
  ```
  
-6. Range can be specified without any step params like below
+7. Range can be specified without any step params like below
 
 ```
 /api/payments/chart?_fields=amount&range=1

lib/xapi.js

@@ -762,6 +762,14 @@ class Xapi {
           isRange)
 
 
+      } else if (req.query && req.query.steppair && req.query.steppair.length > 1) {
+
+        obj = this.mysql.getChartQueryAndParamsFromStepPair(req.app.locals._tableName,
+          req.query._fields,
+          (req.query.steppair.split(',')).map(Number),
+          false)
+
+
       } else {
 
         query = 'select min(??) as min,max(??) as max,stddev(??) as stddev,avg(??) as avg from ??';
@@ -790,6 +798,8 @@ class Xapi {
 
       }
 
+      this.mysql.getWhereClause(req.query._where, req.app.locals._tableName, obj, ' where ')
+
       let results = await
         this.mysql.exec(obj.query, obj.params);
 

lib/xsql.js

@@ -659,6 +659,45 @@ class Xsql {
 
   }
 
+  getChartQueryAndParamsFromStepPair(tableName, columnName, stepArray, isRange = false) {
+
+    let obj = {}
+
+    obj.query = ''
+    obj.params = []
+
+    //console.log('getChartQueryAndParamsFromStepArray',isRange);
+
+    //select ? as ??, count(*) as _count from ?? where ?? between ? and ?
+
+    if (stepArray.length && stepArray.length >= 2 && stepArray.length%2 === 0) {
+
+      for (let i = 0; i < stepArray.length && stepArray.length >= 2; i = i + 2) {
+
+        obj.query = obj.query + dataHelp.getChartQuery();
+
+        if (i + 2 < stepArray.length) {
+          obj.query = obj.query + ' union '
+        }
+
+        obj.params.push((stepArray[i]) + ' to ' + stepArray[i + 1])
+        obj.params.push(columnName)
+        obj.params.push(tableName)
+        obj.params.push(columnName)
+        obj.params.push(stepArray[i])
+        obj.params.push(stepArray[i + 1])
+
+      }
+
+    }
+
+    //console.log('step spread query', obj);
+
+    return obj;
+
+  }
+
+
   getChartQueryAndParamsFromStepArray(tableName, columnName, stepArray, isRange = false) {
 
     let obj = {}

tests/tests.js

@@ -1674,6 +1674,31 @@ describe('xmysql : tests', function () {
 
       });
   });
+
+
+  it('GET /api/payments/chart?_fields=amount&steppair=0,50000,40000,100000 should PASS', function (done) {
+
+    //post to an url with data
+    agent.get('/api/payments/chart?_fields=amount&steppair=0,50000,40000,100000')     //enter url
+      .expect(200)//200 for success 4xx for failure
+      .end(function (err, res) {
+
+        // Handle /api/v error
+        if (err) {
+          return done(err);
+        }
+
+        //validate response
+        res.body.length.should.be.equals(2)
+        res.body[0]['_count'].should.be.equals(231)
+        res.body[1]['_count'].should.be.equals(80)
+
+        return done();
+
+      });
+  });
+
+
   // it('GET /api/xjoin?_join=pl.productlines,_j,pr.products,_j,ord.orderDetails&_on1=(pl.productline,eq,pr.productline)&_on2=(pr.productcode,eq,ord.productcode) should PASS', function (done) {
   //
   //   //post to an url with data