Fix#24 : Xjoin column names to have aliases derived from tablName-alias and columnName.

README.md

@@ -726,7 +726,7 @@ Sql join query:
 
 ```sql
 
-SELECT *
+SELECT pl.field1, pr.field2
 FROM productlines as pl
     JOIN products as pr
         ON pl.productline = pr.productline
@@ -735,14 +735,14 @@ FROM productlines as pl
 
 Equivalent xjoin query API:
 ```
-/api/xjoin?_join=pl.productlines,_j,pr.products&_on1=(pl.productline,eq,pr.productline)
+/api/xjoin?_join=pl.productlines,_j,pr.products&_on1=(pl.productline,eq,pr.productline)&_fields=pl.field1,pr.field2
 ```
 
 #### Multiple tables join
 
 Sql join query:
 ```sql
-SELECT *
+SELECT pl.field1, pr.field2, ord.field3
 FROM productlines as pl
     JOIN products as pr
         ON pl.productline = pr.productline
@@ -753,7 +753,7 @@ FROM productlines as pl
 Equivalent xjoin query API:
 
 ```
-/api/xjoin?_join=pl.productlines,_j,pr.products,_j,ord.orderDetails&_on1=(pl.productline,eq,pr.productline)&_on2=(pr.productcode,eq,ord.productcode)
+/api/xjoin?_join=pl.productlines,_j,pr.products,_j,ord.orderDetails&_on1=(pl.productline,eq,pr.productline)&_on2=(pr.productcode,eq,ord.productcode)&_fields=&_fields=pl.field1,pr.field2,ord.field3
 
 ```
 
@@ -774,6 +774,16 @@ Example to use : _fields, _where, _p, _size in query params
 /api/xjoin?_join=pl.productlines,_j,pr.products&_on1=(pl.productline,eq,pr.productline)&_fields=pl.productline,pr.productName&_size=2&_where=(productName,like,1972~)
 ```
 
+Response:
+
+```
+[{"pl_productline":"Classic Cars","pr_productName":"1972 Alfa Romeo GTA"}]
+```
+
+Please note : 
+Xjoin response has aliases for fields like below aliasTableName + '_' + columnName.   
+eg: pl.productline in _fields query params - returns as pl_productline in response. 
+
 ## Run dynamic queries
 [:arrow_heading_up:](#api-overview)
 

lib/xapi.js

@@ -304,9 +304,12 @@ class Xapi {
     this.mysql.prepareJoinQuery(req, res, obj)
 
     //console.log(obj);
-
+    if(obj.query.length){
       let results = await this.mysql.exec(obj.query, obj.params)
       res.status(200).json(results)
+    } else {
+      res.status(400).json({err: 'Invalid Xjoin request'});
+    }
 
   }
 

lib/xsql.js

@@ -139,6 +139,7 @@ class Xsql {
       }
     }
   }
+
   /**************** END : Cache functions ****************/
 
 
@@ -954,27 +955,38 @@ class Xsql {
     queryParamsObj.query = 'SELECT '
     queryParamsObj.grammarErr = 0;
 
+    while (1) {
+
       /**************** START : get fields ****************/
       if (req.query._fields) {
 
         let fields = req.query._fields.split(',')
 
         // from _fields to - ??, ??, ?? [col1,col2,col3]
-      for (var i = 0; i < fields.length; ++i) {
+        for (var i = 0; i < fields.length && (!queryParamsObj.grammarErr); ++i) {
           if (i) {
             queryParamsObj.query += ','
           }
           queryParamsObj.query += ' ?? '
           queryParamsObj.params.push(fields[i])
+          let aliases = fields[i].split('.');
+          if (aliases.length === 2) {
+            queryParamsObj.query += 'as ' + aliases[0] + '_' + aliases[1];
+            //console.log(queryParamsObj.query);
+          } else {
+            queryParamsObj.grammarErr = 1;
+          }
         }
-
       } else {
+        queryParamsObj.grammarErr = 1;
+      }
 
-      queryParamsObj.query += ' * '
+      queryParamsObj.query += ' from '
 
+      if(queryParamsObj.grammarErr){
+        break;
       }
 
-    queryParamsObj.query += ' from '
       /**************** END : get fields ****************/
 
 
@@ -983,6 +995,7 @@ class Xsql {
       if (joinTables.length < 3) {
         //console.log('grammar error ', joinTables.length);
         queryParamsObj.grammarErr = 1;
+        break;
       }
 
       //console.log('jointables.length', joinTables);
@@ -1016,29 +1029,33 @@ class Xsql {
           break;
         }
 
-      //console.log('- - - - - - -');
         if (i === 0) {
           i = i + 1
         }
-      //console.log('index after loop', i);
       }
       /**************** END : get join + on ****************/
 
       if(queryParamsObj.grammarErr){
-      queryParamsObj.query = ''
-      queryParamsObj.params = []
+        break;
+      } else {
+        this.getWhereClause(req.query._where, ' ignore ', queryParamsObj, ' where ');
+        this._getGrpByHavingOrderBy(req, 'ignore', queryParamsObj, 5)
+        //console.log('after where',queryParamsObj);
       }
 
-    this.getWhereClause(req.query._where, ' ignore ', queryParamsObj, ' where ');
+      break;
 
-    //console.log('after where',queryParamsObj);
+    }
 
-    this._getGrpByHavingOrderBy(req, 'ignore', queryParamsObj, 5)
 
-    return queryParamsObj;
+    if (queryParamsObj.grammarErr) {
+      queryParamsObj.query = ''
+      queryParamsObj.params = []
     }
 
 
+    return queryParamsObj;
+  }
 
 
 }

tests/tests.js

@@ -1599,7 +1599,7 @@ describe('xmysql : tests', function () {
 
     //post to an url with data
     agent.get(apiPrefix + 'xjoin?_join=pl.productlines,_j,pr.products&_on1=(pl.productline,eq,pr.productline)')     //enter url
-      .expect(200)//200 for success 4xx for failure
+      .expect(400)//200 for success 4xx for failure
       .end(function (err, res) {
 
         // Handle /api/v error
@@ -1607,8 +1607,6 @@ describe('xmysql : tests', function () {
           return done(err);
         }
 
-        //validate response
-        Object.keys(res.body[0]).length.should.be.equals(12)
         return done();
 
       });
@@ -1636,6 +1634,24 @@ describe('xmysql : tests', function () {
       });
   });
 
+  it('GET ' + apiPrefix + 'xjoin?_join=pl.productlines,_j,pr.products&_on1=(pl.productline,eq,pr.productline)&_fields=pl_productline,pr.productName should PASS', function (done) {
+
+    //post to an url with data
+    agent.get(apiPrefix + 'xjoin?_join=pl.productlines,_j,pr.products&_on1=(pl.productline,eq,pr.productline)&_fields=pl_productline,pr.productName')     //enter url
+      .expect(400)//200 for success 4xx for failure
+      .end(function (err, res) {
+
+        // Handle /api/v error
+        if (err) {
+          return done(err);
+        }
+
+        return done();
+
+      });
+  });
+
+
   it('GET ' + apiPrefix + 'xjoin?_join=pl.productlines,_j,pr.products&_on1=(pl.productline,eq,pr.productline)&_fields=pl.productline,pr.productName&_size=2 should PASS', function (done) {
 
     //post to an url with data