Add support for DISTINCT

brianc · brianc · commit a9a8a9983b6f · 2013-05-06T12:56:51.000-05:00
usage: `users.select(users.email.distinct())`
diff --git a/lib/column.js b/lib/column.js
@@ -91,6 +91,12 @@ Column.prototype.count = function(alias) {
   return new ColumnNode(context);
 };
 
+Column.prototype.distinct = function() {
+  var context = contextify(this);
+  context.distinct = true;
+  return new ColumnNode(context);
+};
+
 binaryMethod('equals', '=');
 binaryMethod('equal', '=');
 binaryMethod('notEqual', '<>');
diff --git a/lib/dialect/postgres.js b/lib/dialect/postgres.js
@@ -287,11 +287,17 @@ Postgres.prototype.visitColumn = function(columnNode) {
   var table = columnNode.table;
   var inSelectClause = !this._selectOrDeleteEndIndex;
   var txt = "";
+  var closeParen = false;
   if(inSelectClause) {
     if (columnNode.asArray) {
+      closeParen = true;
       txt += this._arrayAggFunctionName+'(';
     } else if (columnNode.aggCount) {
+      closeParen = true;
       txt += 'COUNT(';
+    } else if (columnNode.distinct === true) {
+      closeParen = true;
+      txt += 'DISTINCT('
     }
   }
   if(!this._visitedInsert && !this._visitingUpdateTargetColumn && !this._visitingCreate && !this._visitingAlter) {
@@ -311,7 +317,7 @@ Postgres.prototype.visitColumn = function(columnNode) {
   } else {
     txt += this.quote(columnNode.name);
   }
-  if(inSelectClause && (columnNode.asArray || columnNode.aggCount)) {
+  if(closeParen) {
     txt += ')';
   }
   if(inSelectClause && columnNode.alias) {
diff --git a/lib/node/column.js b/lib/node/column.js
@@ -14,6 +14,7 @@ module.exports = Node.define({
     this.table = config.table;
     this.value = config.getValue();
     this.dataType = config.dataType;
+    this.distinct = config.distinct;
   },
   as: function(alias) {
     this.alias = alias;
diff --git a/test/dialects/distinct-tests.js b/test/dialects/distinct-tests.js
@@ -0,0 +1,9 @@
+'use strict';
+
+var Harness = require('./support');
+var user = Harness.defineUserTable();
+
+Harness.test({
+  query : user.select(user.id.distinct()),
+  pg    : 'SELECT DISTINCT("user"."id") FROM "user"'
+});
