added support for delete

lib/dialects/mssql/query-generator.js

@@ -189,7 +189,11 @@ module.exports = (function() {
     */
     /* istanbul ignore next */
     deleteQuery: function(tableName, where, options) {
-      throwMethodUndefined('deleteQuery');
+          console.log('where:', where);
+
+      var query = SqlGenerator.deleteSql(tableName, where);
+
+      return query;
     },
 
     /*

lib/dialects/mssql/sql-generator.js

@@ -275,6 +275,16 @@ module.exports = {
 
     return Utils._.template(query)(replacements);
   },
+  deleteSql: function(tableName, where) {
+    var query = "DELETE FROM <%= table %> <%= where %>";
+    var replacements = {
+      table: tableName,
+      where: this.getWhereClause(where, tableName)
+    };
+
+    return Utils._.template(query)(replacements);
+  },
+
   addColumnSql: function(key, dataType){
     var attribute = Utils._.template('<%= key %> <%= definition %>')({
       key: quoteIdentifier(key),
@@ -546,13 +556,16 @@ module.exports = {
     //console.log(where);
     //console.log(tableName);
     for(var key in where){
-      if(tableName){
-        query.push(quoteIdentifier(tableName) + '.' + quoteIdentifier(key));
-      }else{
-        query.push(quoteIdentifier(key));
+      var val = where[key];
+      var operator = '=';
+
+      if (val == 'NULL') {
+        operator = 'IS';
       }
-      query.push('=');
-      query.push(where[key]);
+
+      query.push(quoteIdentifier(tableName) + '.' + quoteIdentifier(key));
+      query.push(operator);
+      query.push(val);
     }
     return query.join(' ');
   }};