fix: issue with reused select cqns (#505)

db-service/lib/SQLService.js

@@ -123,10 +123,13 @@ class SQLService extends DatabaseService {
     }
 
     const { sql, values, cqn } = this.cqn2sql(query, data)
+    const expand = query.SELECT.expand
+    delete query.SELECT.expand
+
     let ps = await this.prepare(sql)
     let rows = await ps.all(values)
     if (rows.length)
-      if (cqn.SELECT.expand) rows = rows.map(r => (typeof r._json_ === 'string' ? JSON.parse(r._json_) : r._json_ || r))
+      if (expand) rows = rows.map(r => (typeof r._json_ === 'string' ? JSON.parse(r._json_) : r._json_ || r))
 
     if (cds.env.features.stream_compat) {
       if (query._streaming) {

hana/lib/HANAService.js

@@ -111,6 +111,8 @@ class HANAService extends SQLService {
     // Will return multiple rows with objects inside
     query.SELECT.expand = 'root'
     const { cqn, temporary, blobs, withclause, values } = this.cqn2sql(query, data)
+    delete query.SELECT.expand
+
     // REVISIT: add prepare options when param:true is used
     const sqlScript = this.wrapTemporary(temporary, withclause, blobs)
     let rows = (values?.length || blobs.length > 0)

test/scenarios/bookshop/read.test.js

@@ -79,6 +79,19 @@ describe('Bookshop - Read', () => {
     expect(res.length).to.be.eq(2)
   })
 
+  test('reuse already executed select as subselect', async () => {
+    let s = SELECT.columns('ID').from('sap.capire.bookshop.Books')
+    let res = await s
+
+    res = await SELECT.one.from('sap.capire.bookshop.Books as b')
+      .join('sap.capire.bookshop.Authors as a')
+      .on('a.ID = b.author_ID')
+      .columns('a.name', 'b.title')
+      .where('b.ID in', s)
+      .orderBy('b.ID')
+    expect(res).to.deep.eq({"name": "Emily Brontë", "title": "Wuthering Heights"})
+  })
+
   test('Expand Book', async () => {
     const res = await GET(
       '/admin/Books(252)?$select=title&$expand=author($select=name;$expand=books($select=title))',