Fix NULL values in INTO SQL() - handle null and undefined properly

Co-authored-by: mathiasrw <[email protected]>

Author: Copilot

src/830into.js

@@ -36,25 +36,31 @@ alasql.into.SQL = function (filename, opts, data, columns, cb) {
 			})
 			.join(',');
 		s += ') VALUES (';
-		s += columns.map(function (col) {
-			var val = data[i][col.columnid];
-			if (col.typeid) {
-				if (
-					col.typeid === 'STRING' ||
-					col.typeid === 'VARCHAR' ||
-					col.typeid === 'NVARCHAR' ||
-					col.typeid === 'CHAR' ||
-					col.typeid === 'NCHAR'
-				) {
-					val = "'" + escapeqq(val) + "'";
+		s += columns
+			.map(function (col) {
+				var val = data[i][col.columnid];
+				// Handle null and undefined values
+				if (val === null || val === undefined) {
+					return 'NULL';
 				}
-			} else {
-				if (typeof val == 'string') {
-					val = "'" + escapeqq(val) + "'";
+				if (col.typeid) {
+					if (
+						col.typeid === 'STRING' ||
+						col.typeid === 'VARCHAR' ||
+						col.typeid === 'NVARCHAR' ||
+						col.typeid === 'CHAR' ||
+						col.typeid === 'NCHAR'
+					) {
+						val = "'" + escapeqq(val) + "'";
+					}
+				} else {
+					if (typeof val == 'string') {
+						val = "'" + escapeqq(val) + "'";
+					}
 				}
-			}
-			return val;
-		});
+				return val;
+			})
+			.join(',');
 		s += ');\n';
 	}
 	//	if(filename === '') {