From 8f4550a802f2e8c2556fc360c8f548064eaf17f4 Mon Sep 17 00:00:00 2001
From: Ezekiel Keator <20361796+tastypackets@users.noreply.github.com>
Date: Tue, 10 Nov 2020 20:02:45 -0600
Subject: [PATCH] Do not include null in COUNT or AVG fixes #1251 (#1252)

---
 src/423groupby.js |  28 +++++++++--
 test/test812.js   | 115 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 139 insertions(+), 4 deletions(-)
 create mode 100644 test/test812.js

diff --git a/src/423groupby.js b/src/423groupby.js
index f2b7225ae4..360b2dbcc0 100755
--- a/src/423groupby.js
+++ b/src/423groupby.js
@@ -166,7 +166,15 @@ if(false) {
 						} else {
 							//						return "'"+colas+'\':(typeof '+colexp+' != "undefined")?1:0,';
 							//					} else {
-							return "'" + colas + "':(typeof " + colexp + ' != "undefined")?1:0,';
+							return (
+								"'" +
+								colas +
+								"':(typeof " +
+								colexp +
+								' == "undefined" || ' +
+								colexp +
+								' === null) ? 0 : 1,'
+							);
 						}
 
 						//				else if(col.aggregatorid == 'MIN') { return "'"+col.as+'\':r[\''+col.as+'\'],'; }
@@ -189,7 +197,9 @@ if(false) {
 							colas +
 							"':(typeof " +
 							colexp +
-							' != "undefined")?1:0,'
+							' == "undefined" || ' +
+							colexp +
+							' === null) ? 0 : 1,'
 						);
 					} else if (col.aggregatorid === 'AGGR') {
 						aft += ",g['" + colas + "']=" + col.expression.toJS('g', -1);
@@ -300,7 +310,17 @@ if(false) {
 						if (col.expression.columnid === '*') {
 							return pre + "g['" + colas + "']++;" + post;
 						} else {
-							return pre + 'if(typeof ' + colexp + '!="undefined") g[\'' + colas + "']++;" + post;
+							return (
+								pre +
+								'if(typeof ' +
+								colexp +
+								'!="undefined" && ' +
+								colexp +
+								" !== null) g['" +
+								colas +
+								"']++;" +
+								post
+							);
 						}
 					} else if (col.aggregatorid === 'ARRAY') {
 						return pre + "g['" + colas + "'].push(" + colexp + ');' + post;
@@ -327,7 +347,7 @@ if(false) {
 							')||0;' +
 							"g['_COUNT_" +
 							colas +
-							'\']+=(typeof y!="undefined")?1:0;' +
+							'\']+=(typeof y == "undefined" || y === null) ? 0 : 1;' +
 							"g['" +
 							colas +
 							"']=g['_SUM_" +
diff --git a/test/test812.js b/test/test812.js
new file mode 100644
index 0000000000..8de565573a
--- /dev/null
+++ b/test/test812.js
@@ -0,0 +1,115 @@
+if (typeof exports === 'object') {
+	var assert = require('assert');
+	var alasql = require('..');
+} else {
+	__dirname = '.';
+}
+
+describe('Test 243 AVG bug', function () {
+	it('1. Does not count null when using GROUP BY', function (done) {
+		var data = [
+			{a: 1, b: 2, c: null},
+			{a: 1, b: null, c: null},
+			{a: null, b: null, c: null},
+			{a: 1, b: undefined, c: null},
+			{a: null, b: 2, c: null},
+		];
+		var res = alasql(
+			'SELECT COUNT(*) as all_rows, COUNT(a) as a, COUNT(b) as b, COUNT(c) as c FROM ?',
+			[data]
+		);
+		assert.deepEqual(res, [
+			{
+				all_rows: 5,
+				a: 3,
+				b: 2,
+				c: 0,
+			},
+		]);
+		done();
+	});
+
+	it('2. Does not count null when using GROUP BY', function (done) {
+		var data = [{a: 1}, {a: 1}, {a: 2}, {a: 3}, {a: 1}, {a: 2}, {a: undefined}, {a: null}];
+		var res = alasql('SELECT a, COUNT(*) as b, COUNT(a) as c FROM ? GROUP BY a', [data]);
+		assert.deepEqual(res, [
+			{a: 1, b: 3, c: 3},
+			{a: 2, b: 2, c: 2},
+			{a: 3, b: 1, c: 1},
+			{a: undefined, b: 1, c: 0},
+			{a: null, b: 1, c: 0},
+		]);
+		done();
+	});
+
+	it('3. Does not count null in AVG', function (done) {
+		var arr = [
+			{
+				person: 1,
+				sold: 5,
+			},
+			{
+				person: 2,
+				sold: 10,
+			},
+			{
+				person: 1,
+				sold: 20,
+			},
+			{
+				person: 3,
+				sold: 40,
+			},
+			{
+				person: 3,
+				sold: null,
+			},
+		];
+
+		var res = alasql('SELECT VALUE AVG(sold) FROM ?', [arr]);
+		assert.equal(res, 18.75);
+		done();
+	});
+
+	it('4. Does not count null when using AVG and GROUP BY', function (done) {
+		var arr = [
+			{
+				person: 1,
+				sold: 5,
+			},
+			{
+				person: 1,
+				sold: null,
+			},
+			{
+				person: 2,
+				sold: 10,
+			},
+			{
+				person: 1,
+				sold: 20,
+			},
+			{
+				person: 1,
+				sold: null,
+			},
+			{
+				person: 3,
+				sold: 40,
+			},
+			{
+				person: 3,
+				sold: null,
+			},
+		];
+
+		var res = alasql('SELECT person, avg(sold) FROM ? GROUP BY person', [arr]);
+
+		assert(res, [
+			{person: 1, 'AVG(sold)': 12.5},
+			{person: 2, 'AVG(sold)': 10},
+			{person: 3, 'AVG(sold)': 40},
+		]);
+		done();
+	});
+});