Adds possibility to pass an Array to aggregate functions as the columns to aggregate

Example: SELECT MIN(a, b, c) ..

Author: dresende

lib/Select.js

@@ -140,10 +140,20 @@ function SelectQuery(Dialect) {
 					for (j = 0; j < sql.from[i].select.length; j++) {
 						str = sql.from[i].select[j].f + "(";
 
-						if (sql.from.length == 1) {
-							str += (sql.from[i].select[j].c ? Dialect.escapeId(sql.from[i].select[j].c) : "*");
+						if (sql.from[i].select[j].c && !Array.isArray(sql.from[i].select[j].c)) {
+							sql.from[i].select[j].c = [ sql.from[i].select[j].c ];
+						}
+
+						if (Array.isArray(sql.from[i].select[j].c)) {
+							str += sql.from[i].select[j].c.map(function (el) {
+								if (sql.from.length == 1) {
+									return Dialect.escapeId(el);
+								} else {
+									return Dialect.escapeId(sql.from[i].a, el);
+								}
+							}).join(", ");
 						} else {
-							str += (sql.from[i].select[j].c ? Dialect.escapeId(sql.from[i].a, sql.from[i].select[j].c) : "*");
+							str += "*";
 						}
 
 						str += ")";

test/integration/test-select-aggregate.js

@@ -15,3 +15,8 @@ assert.equal(
 	common.Select().from('table1').avg().max('col1').min('col2').build(),
 	"SELECT AVG(MAX(`col1`)), MIN(`col2`) FROM `table1`"
 );
+
+assert.equal(
+	common.Select().from('table1').avg().max([ 'col1', 'col2' ]).min('col3').build(),
+	"SELECT AVG(MAX(`col1`, `col2`)), MIN(`col3`) FROM `table1`"
+);