Fix subqueries for CREATE VIEW to close #1154 (#2406)

Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: mathiasrw <[email protected]>
Co-authored-by: Mathias Wulff <[email protected]>

Author: Copilot

src/41exists.js

@@ -32,6 +32,12 @@ yy.ExistsValue = class ExistsValue {
 alasql.precompile = function (statement, databaseid, params) {
 	if (!statement) return;
 	statement.params = params;
+	// For CREATE VIEW statements, move queries to the select object
+	// so they can be compiled later when the view is first used
+	if (statement.view && statement.select && statement.queries) {
+		statement.select.queries = statement.queries;
+		return;
+	}
 	if (statement.queries) {
 		statement.queriesfn = statement.queries.map(function (q) {
 			var nq = q.compile(databaseid || statement.database.databaseid);

src/420from.js

@@ -71,7 +71,12 @@ yy.Select.prototype.compileFrom = function (query) {
 				};
 			} else if (alasql.databases[source.databaseid].tables[source.tableid].view) {
 				source.datafn = (query, params, cb, idx, alasql) => {
-					let res = alasql.databases[source.databaseid].tables[source.tableid].select(params);
+					let table = alasql.databases[source.databaseid].tables[source.tableid];
+					// Lazily compile the view's select on first use
+					if (!table.select && table.viewSelect) {
+						table.select = table.viewSelect.compile(table.viewDatabaseid);
+					}
+					let res = table.select(params);
 					if (cb) res = cb(res, idx, query);
 					return res;
 				};

src/60createtable.js

@@ -317,7 +317,9 @@ yy.CreateTable.prototype.execute = function (databaseid, params, cb) {
 	//Used in 420from queryfn when table.view = true!
 	if (this.view && this.select) {
 		table.view = true;
-		table.select = this.select.compile(this.table.databaseid || databaseid);
+		// Store the uncompiled select statement and databaseid for lazy compilation
+		table.viewSelect = this.select;
+		table.viewDatabaseid = this.table.databaseid || databaseid;
 	}
 
 	if (db.engineid) {

test/test1154.js

@@ -0,0 +1,51 @@
+if (typeof exports === 'object') {
+	var assert = require('assert');
+	var alasql = require('..');
+}
+
+describe('Test 950 - CREATE VIEW with subquery', function () {
+	const test = '950';
+
+	before(function () {
+		alasql('create database test' + test);
+		alasql('use test' + test);
+	});
+
+	after(function () {
+		alasql('drop database test' + test);
+	});
+
+	it('A) Create tables', function () {
+		alasql('create table sub_table(id int)');
+		alasql('create table from_table(id int)');
+		alasql('insert into sub_table values (1), (2), (3)');
+		alasql('insert into from_table values (100)');
+	});
+
+	it('B) Test the query works without view', function () {
+		var result = alasql('select (select count(id) from sub_table) as amount from from_table');
+		assert.deepEqual(result, [{amount: 3}]);
+	});
+
+	it('C) Create view with subquery', function () {
+		// This should not throw "Table does not exist: sub_table" error
+		alasql(
+			'create view new_view as select (select count(id) from sub_table) as amount from from_table'
+		);
+	});
+
+	it('D) Query from view', function () {
+		var result = alasql('select * from new_view');
+		assert.deepEqual(result, [{amount: 3}]);
+	});
+
+	it('E) View should reflect data changes', function () {
+		alasql('insert into sub_table values (4), (5)');
+		var result = alasql('select * from new_view');
+		assert.deepEqual(result, [{amount: 5}]);
+	});
+
+	it('F) Drop view', function () {
+		alasql('drop view new_view');
+	});
+});