From b579da84231cd18f0ed2dd706b6fce620a0a5d51 Mon Sep 17 00:00:00 2001
From: Paul <paul.erlenwein@gmail.com>
Date: Mon, 27 Jan 2025 16:32:42 +0100
Subject: [PATCH] fix: groupby path expression with overlapping identifier
 (#992)

Currently, the HANA service is unable to `GROUP BY foobar.foobar`,
raising an error like `invalid column name: foobar.foobar`, if the query
includes an aggregation and `sql syntax error: incorrect syntax near
"FROM"`, if it does not. The problem is caused by the overlapping column
names and the HANA service not correctly injecting the column groupby
requires into the parent select - if the parent includes a column with
the same `column_name` as the 'grouped-by' column.

This fix enables the required injection, by skipping the overlapping
names check for columns that contain a select.

---------

Co-authored-by: Bob den Os <108393871+BobdenOs@users.noreply.github.com>
Co-authored-by: Johannes Vogel <31311694+johannes-vogel@users.noreply.github.com>
---
 hana/lib/HANAService.js                              |  2 +-
 test/compliance/SELECT.test.js                       | 12 ++++++++++++
 .../compliance/resources/db/complex/associations.cds |  1 +
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/hana/lib/HANAService.js b/hana/lib/HANAService.js
index e28aff781..4024e122a 100644
--- a/hana/lib/HANAService.js
+++ b/hana/lib/HANAService.js
@@ -549,7 +549,7 @@ class HANAService extends SQLService {
                     // if (col.ref?.length === 1) { col.ref.unshift(parent.as) }
                     if (col.ref?.length > 1) {
                       const colName = this.column_name(col)
-                      if (!parent.SELECT.columns.some(c => this.column_name(c) === colName)) {
+                      if (!parent.SELECT.columns.some(c => !c.elements && this.column_name(c) === colName)) {
                         const isSource = from => {
                           if (from.as === col.ref[0]) return true
                           return from.args?.some(a => {
diff --git a/test/compliance/SELECT.test.js b/test/compliance/SELECT.test.js
index 786193446..a25b5029d 100644
--- a/test/compliance/SELECT.test.js
+++ b/test/compliance/SELECT.test.js
@@ -635,6 +635,18 @@ describe('SELECT', () => {
       const res = await cds.run(cqn)
       assert.strictEqual(res.length, 3, 'Ensure that all rows are coming back')
     })
+
+    test('navigation with duplicate identifier in path', async () => {
+      const { Books } = cds.entities('complex.associations')
+      const res = await cds.ql`SELECT name { name } FROM ${Books} GROUP BY name.name`
+      assert.strictEqual(res.length, 1, 'Ensure that all rows are coming back')
+    })
+
+    test('navigation with duplicate identifier in path and aggregation', async () => {
+      const { Books } = cds.entities('complex.associations')
+      const res = await cds.ql`SELECT name { name }, count(1) as total FROM ${Books} GROUP BY name.name`
+      assert.strictEqual(res.length, 1, 'Ensure that all rows are coming back')
+    })
   })
 
   describe('having', () => {
diff --git a/test/compliance/resources/db/complex/associations.cds b/test/compliance/resources/db/complex/associations.cds
index 6f5216285..5fc0edb8c 100644
--- a/test/compliance/resources/db/complex/associations.cds
+++ b/test/compliance/resources/db/complex/associations.cds
@@ -4,6 +4,7 @@ entity Books {
   key ID : Integer;
   title  : String(111);
   author : Association to Authors;
+  name   : Association to Authors on $self.author.ID = name.ID;
 }
 
 entity Authors {