From 5fbfd8d8cbe326f79d6cffe3b6f91de40642068b Mon Sep 17 00:00:00 2001
From: I543501 <56645452+larslutz96@users.noreply.github.com>
Date: Thu, 9 Jan 2025 15:06:31 +0100
Subject: [PATCH 1/7] Update cqn2sql.js

---
 db-service/lib/cqn2sql.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/db-service/lib/cqn2sql.js b/db-service/lib/cqn2sql.js
index 72cd82d1a..d8d1514e7 100644
--- a/db-service/lib/cqn2sql.js
+++ b/db-service/lib/cqn2sql.js
@@ -875,7 +875,13 @@ class CQN2SQLRenderer {
       : _not_null(i - 1) && _not_null(i + 1)
         ? '<>'
         : this.is_distinct_from_
-
+    
+    // Wrap not with functions with coalesce to always return true or false
+    if (x === 'not' && typeof xpr[i + 1] !== 'string' && 'func' in xpr[i + 1]) {
+      xpr[i + 1] = { args: [xpr[i + 1], { val: false, param: false }], func: 'coalesce' }
+      return x
+    } 
+    
     else return x
 
     function _inline_null(n) {

From 9b8d04a27996703497b48185435f8843733f5db5 Mon Sep 17 00:00:00 2001
From: I543501 <56645452+larslutz96@users.noreply.github.com>
Date: Fri, 10 Jan 2025 10:53:08 +0100
Subject: [PATCH 2/7] only use coalesce for starts and endswith

---
 db-service/lib/cql-functions.js | 4 ++--
 db-service/lib/cqn2sql.js       | 6 ------
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/db-service/lib/cql-functions.js b/db-service/lib/cql-functions.js
index 2f1f8f7f0..df0630978 100644
--- a/db-service/lib/cql-functions.js
+++ b/db-service/lib/cql-functions.js
@@ -75,7 +75,7 @@ const StandardFunctions = {
    * @param {string} y
    * @returns {string}
    */
-  startswith: (x, y) => `instr(${x},${y}) = 1`, // sqlite instr is 1 indexed
+  startswith: (x, y) => `coalesce(instr(${x},${y}) = 1,false)`, // sqlite instr is 1 indexed
   // takes the end of the string of the size of the target and compares it with the target
   /**
    * Generates SQL statement that produces a boolean value indicating whether the first string ends with the second string
@@ -83,7 +83,7 @@ const StandardFunctions = {
    * @param {string} y
    * @returns {string}
    */
-  endswith: (x, y) => `substr(${x}, length(${x}) + 1 - length(${y})) = ${y}`,
+  endswith: (x, y) => `coalesce(substr(${x}, length(${x}) + 1 - length(${y})) = ${y},false)`,
   /**
    * Generates SQL statement that produces the substring of a given string
    * @example
diff --git a/db-service/lib/cqn2sql.js b/db-service/lib/cqn2sql.js
index d8d1514e7..8975ecf68 100644
--- a/db-service/lib/cqn2sql.js
+++ b/db-service/lib/cqn2sql.js
@@ -876,12 +876,6 @@ class CQN2SQLRenderer {
         ? '<>'
         : this.is_distinct_from_
     
-    // Wrap not with functions with coalesce to always return true or false
-    if (x === 'not' && typeof xpr[i + 1] !== 'string' && 'func' in xpr[i + 1]) {
-      xpr[i + 1] = { args: [xpr[i + 1], { val: false, param: false }], func: 'coalesce' }
-      return x
-    } 
-    
     else return x
 
     function _inline_null(n) {

From 424a240305acfefb96f0449ab67c78f3d2141f67 Mon Sep 17 00:00:00 2001
From: I543501 <56645452+larslutz96@users.noreply.github.com>
Date: Fri, 10 Jan 2025 10:53:33 +0100
Subject: [PATCH 3/7] Update cqn2sql.js

---
 db-service/lib/cqn2sql.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/db-service/lib/cqn2sql.js b/db-service/lib/cqn2sql.js
index 8975ecf68..72cd82d1a 100644
--- a/db-service/lib/cqn2sql.js
+++ b/db-service/lib/cqn2sql.js
@@ -875,7 +875,7 @@ class CQN2SQLRenderer {
       : _not_null(i - 1) && _not_null(i + 1)
         ? '<>'
         : this.is_distinct_from_
-    
+
     else return x
 
     function _inline_null(n) {

From bac3346b38a60fe25efe50f73a9bd0b025d22b40 Mon Sep 17 00:00:00 2001
From: I543501 <56645452+larslutz96@users.noreply.github.com>
Date: Fri, 10 Jan 2025 11:10:05 +0100
Subject: [PATCH 4/7] tests

---
 test/scenarios/bookshop/funcs.test.js | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/test/scenarios/bookshop/funcs.test.js b/test/scenarios/bookshop/funcs.test.js
index b634f101b..88de79a53 100644
--- a/test/scenarios/bookshop/funcs.test.js
+++ b/test/scenarios/bookshop/funcs.test.js
@@ -42,6 +42,15 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
+    test('not endswith', async () => {
+      const { Books } = cds.entities('sap.capire.bookshop')
+      await cds.run(INSERT.into(Books).columns(['ID']).rows([123]))
+      const res = await GET(`/browse/Books?$filter=not endswith(title,'Sturm')`)
+      expect(res.status).to.be.eq(200)
+      expect(res.data.value.some(item => item.ID === 123)).to.be.true
+      await cds.run(DELETE.from(Books).where({ ID: 123 }))
+    })
+
     test('indexof', async () => {
       const res = await GET(`/browse/Books?$filter=indexof(author,'Allen') eq 6`)
 
@@ -67,6 +76,15 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
+    test('not startswith', async () => {
+      const { Books } = cds.entities('sap.capire.bookshop')
+      await cds.run(INSERT.into(Books).columns(['ID']).rows([123]))
+      const res = await GET(`/browse/Books?$filter=not startswith(title,'Sturm')`)
+      expect(res.status).to.be.eq(200)
+      expect(res.data.value.some(item => item.ID === 123)).to.be.true
+      await cds.run(DELETE.from(Books).where({ ID: 123 }))
+    })
+
     test('substring', async () => {
       const [three, two, negative] = await Promise.all([
         GET(`/browse/Books?$filter=substring(author,1,2) eq 'dg'`),

From 504bcb220a4266bffb182b54175b0b30915701b4 Mon Sep 17 00:00:00 2001
From: I543501 <56645452+larslutz96@users.noreply.github.com>
Date: Fri, 10 Jan 2025 11:49:22 +0100
Subject: [PATCH 5/7] Update funcs.test.js

---
 test/scenarios/bookshop/funcs.test.js | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/test/scenarios/bookshop/funcs.test.js b/test/scenarios/bookshop/funcs.test.js
index 88de79a53..ef177bdc0 100644
--- a/test/scenarios/bookshop/funcs.test.js
+++ b/test/scenarios/bookshop/funcs.test.js
@@ -42,13 +42,13 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
-    test('not endswith', async () => {
+    test('not endswith findes null', async () => {
       const { Books } = cds.entities('sap.capire.bookshop')
-      await cds.run(INSERT.into(Books).columns(['ID']).rows([123]))
-      const res = await GET(`/browse/Books?$filter=not endswith(title,'Sturm')`)
+      await cds.run(INSERT.into(Books).columns(['ID']).rows([456]))
+      const res = await GET(`/browse/Books?$filter=not endswith(title,'höhe')`)
       expect(res.status).to.be.eq(200)
-      expect(res.data.value.some(item => item.ID === 123)).to.be.true
-      await cds.run(DELETE.from(Books).where({ ID: 123 }))
+      expect(res.data.value.some(item => item.ID === 456)).to.be.true
+      await cds.run(DELETE.from(Books).where({ ID: 456 }))
     })
 
     test('indexof', async () => {
@@ -76,13 +76,13 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
-    test('not startswith', async () => {
+    test('not startswith finds null', async () => {
       const { Books } = cds.entities('sap.capire.bookshop')
-      await cds.run(INSERT.into(Books).columns(['ID']).rows([123]))
+      await cds.run(INSERT.into(Books).columns(['ID']).rows([456]))
       const res = await GET(`/browse/Books?$filter=not startswith(title,'Sturm')`)
       expect(res.status).to.be.eq(200)
-      expect(res.data.value.some(item => item.ID === 123)).to.be.true
-      await cds.run(DELETE.from(Books).where({ ID: 123 }))
+      expect(res.data.value.some(item => item.ID === 456)).to.be.true
+      await cds.run(DELETE.from(Books).where({ ID: 456 }))
     })
 
     test('substring', async () => {

From a44e5b5cdc22efe98f3262852039679b91237210 Mon Sep 17 00:00:00 2001
From: I543501 <56645452+larslutz96@users.noreply.github.com>
Date: Fri, 10 Jan 2025 12:01:23 +0100
Subject: [PATCH 6/7] use existing test in SELECT.js

---
 test/compliance/SELECT.test.js        |  6 ++++++
 test/scenarios/bookshop/funcs.test.js | 18 ------------------
 2 files changed, 6 insertions(+), 18 deletions(-)

diff --git a/test/compliance/SELECT.test.js b/test/compliance/SELECT.test.js
index 786193446..03ff8da90 100644
--- a/test/compliance/SELECT.test.js
+++ b/test/compliance/SELECT.test.js
@@ -474,6 +474,7 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: [CXL`not startswith(string,${'n'})`] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
+      assert.strictEqual(res[1].string, null)
     })
 
     test('deep nested boolean function w/o operator', async () => {
@@ -488,6 +489,7 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: [CXL`not startswith(string,${'n'}) and not startswith(string,${'n'})`] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
+      assert.strictEqual(res[1].string, null)
     })
 
     test('multiple levels of not negations of expressions', async () => {
@@ -495,6 +497,7 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: ['not', { xpr: ['not', CXL`not startswith(string,${'n'})`] }] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
+      assert.strictEqual(res[1].string, null)
     })
 
     test('multiple not in a single deep nested expression', async () => {
@@ -509,6 +512,7 @@ describe('SELECT', () => {
           throw err
         }
         assert.strictEqual(res[0].string, 'yes')
+        assert.strictEqual(res[1].string, null)
       })
     })
 
@@ -517,6 +521,7 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: ['not', { xpr: ['not', CXL`not startswith(string,${'n'}) and not startswith(string,${'n'})`] }] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
+      assert.strictEqual(res[1].string, null)
     })
 
     test('multiple levels of not negations of expression with multiple not in a single expression', async () => {
@@ -531,6 +536,7 @@ describe('SELECT', () => {
           throw err
         }
         assert.strictEqual(res[0].string, 'yes')
+        assert.strictEqual(res[1].string, null)
       })
     })
 
diff --git a/test/scenarios/bookshop/funcs.test.js b/test/scenarios/bookshop/funcs.test.js
index ef177bdc0..b634f101b 100644
--- a/test/scenarios/bookshop/funcs.test.js
+++ b/test/scenarios/bookshop/funcs.test.js
@@ -42,15 +42,6 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
-    test('not endswith findes null', async () => {
-      const { Books } = cds.entities('sap.capire.bookshop')
-      await cds.run(INSERT.into(Books).columns(['ID']).rows([456]))
-      const res = await GET(`/browse/Books?$filter=not endswith(title,'höhe')`)
-      expect(res.status).to.be.eq(200)
-      expect(res.data.value.some(item => item.ID === 456)).to.be.true
-      await cds.run(DELETE.from(Books).where({ ID: 456 }))
-    })
-
     test('indexof', async () => {
       const res = await GET(`/browse/Books?$filter=indexof(author,'Allen') eq 6`)
 
@@ -76,15 +67,6 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
-    test('not startswith finds null', async () => {
-      const { Books } = cds.entities('sap.capire.bookshop')
-      await cds.run(INSERT.into(Books).columns(['ID']).rows([456]))
-      const res = await GET(`/browse/Books?$filter=not startswith(title,'Sturm')`)
-      expect(res.status).to.be.eq(200)
-      expect(res.data.value.some(item => item.ID === 456)).to.be.true
-      await cds.run(DELETE.from(Books).where({ ID: 456 }))
-    })
-
     test('substring', async () => {
       const [three, two, negative] = await Promise.all([
         GET(`/browse/Books?$filter=substring(author,1,2) eq 'dg'`),

From eb9138be7fed77cdd9e4310ac7ff3c85ff7bb9bd Mon Sep 17 00:00:00 2001
From: I543501 <56645452+larslutz96@users.noreply.github.com>
Date: Fri, 10 Jan 2025 13:34:18 +0100
Subject: [PATCH 7/7] add postgres coalesce

---
 postgres/lib/cql-functions.js         |  4 ++--
 test/compliance/SELECT.test.js        |  6 ------
 test/scenarios/bookshop/funcs.test.js | 18 ++++++++++++++++++
 3 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/postgres/lib/cql-functions.js b/postgres/lib/cql-functions.js
index 6c91c152b..009ba98e5 100644
--- a/postgres/lib/cql-functions.js
+++ b/postgres/lib/cql-functions.js
@@ -10,8 +10,8 @@ const StandardFunctions = {
   countdistinct: x => `count(distinct ${x.val || x || '*'})`,
   contains: (...args) => `(coalesce(strpos(${args}),0) > 0)`,
   indexof: (x, y) => `strpos(${x},${y}) - 1`, // strpos is 1 indexed
-  startswith: (x, y) => `strpos(${x},${y}) = 1`, // strpos is 1 indexed
-  endswith: (x, y) => `substr(${x},length(${x}) + 1 - length(${y})) = ${y}`,
+  startswith: (x, y) => `coalesce(strpos(${x},${y}) = 1,false)`, // strpos is 1 indexed
+  endswith: (x, y) => `coalesce(substr(${x},length(${x}) + 1 - length(${y})) = ${y},false)`,
   matchesPattern: (x, y) => `regexp_like(${x}, ${y})`,
   matchespattern: (x, y) => `regexp_like(${x}, ${y})`,
 
diff --git a/test/compliance/SELECT.test.js b/test/compliance/SELECT.test.js
index 03ff8da90..786193446 100644
--- a/test/compliance/SELECT.test.js
+++ b/test/compliance/SELECT.test.js
@@ -474,7 +474,6 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: [CXL`not startswith(string,${'n'})`] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
-      assert.strictEqual(res[1].string, null)
     })
 
     test('deep nested boolean function w/o operator', async () => {
@@ -489,7 +488,6 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: [CXL`not startswith(string,${'n'}) and not startswith(string,${'n'})`] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
-      assert.strictEqual(res[1].string, null)
     })
 
     test('multiple levels of not negations of expressions', async () => {
@@ -497,7 +495,6 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: ['not', { xpr: ['not', CXL`not startswith(string,${'n'})`] }] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
-      assert.strictEqual(res[1].string, null)
     })
 
     test('multiple not in a single deep nested expression', async () => {
@@ -512,7 +509,6 @@ describe('SELECT', () => {
           throw err
         }
         assert.strictEqual(res[0].string, 'yes')
-        assert.strictEqual(res[1].string, null)
       })
     })
 
@@ -521,7 +517,6 @@ describe('SELECT', () => {
       const query = CQL`SELECT * FROM ${string} WHERE ${{ xpr: ['not', { xpr: ['not', CXL`not startswith(string,${'n'}) and not startswith(string,${'n'})`] }] }} ORDER BY string DESC`
       const res = await cds.run(query)
       assert.strictEqual(res[0].string, 'yes')
-      assert.strictEqual(res[1].string, null)
     })
 
     test('multiple levels of not negations of expression with multiple not in a single expression', async () => {
@@ -536,7 +531,6 @@ describe('SELECT', () => {
           throw err
         }
         assert.strictEqual(res[0].string, 'yes')
-        assert.strictEqual(res[1].string, null)
       })
     })
 
diff --git a/test/scenarios/bookshop/funcs.test.js b/test/scenarios/bookshop/funcs.test.js
index b634f101b..585a5daee 100644
--- a/test/scenarios/bookshop/funcs.test.js
+++ b/test/scenarios/bookshop/funcs.test.js
@@ -42,6 +42,15 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
+    test('not endswith finds null', async () => {
+      const { Books } = cds.entities('sap.capire.bookshop')
+      await cds.run(INSERT({ ID: 123, title: 'Harry Potter', stock: undefined }).into(Books))
+      const res = await GET(`/browse/Books?$filter=not endswith(author,'Poe')`)
+      expect(res.status).to.be.eq(200)
+      expect(res.data.value.some(item => item.ID === 123)).to.be.true
+      await cds.run(DELETE.from(Books).where({ ID: 123 }))
+    })
+
     test('indexof', async () => {
       const res = await GET(`/browse/Books?$filter=indexof(author,'Allen') eq 6`)
 
@@ -67,6 +76,15 @@ describe('Bookshop - Functions', () => {
       expect(wrong.data.value.length).to.be.eq(0)
     })
 
+    test('not startswith finds null', async () => {
+      const { Books } = cds.entities('sap.capire.bookshop')
+      await cds.run(INSERT({ ID: 123, title: 'Harry Potter', stock: undefined }).into(Books))
+      const res = await GET(`/browse/Books?$filter=not startswith(author,'Poe')`)
+      expect(res.status).to.be.eq(200)
+      expect(res.data.value.some(item => item.ID === 123)).to.be.true
+      await cds.run(DELETE.from(Books).where({ ID: 123 }))
+    })
+
     test('substring', async () => {
       const [three, two, negative] = await Promise.all([
         GET(`/browse/Books?$filter=substring(author,1,2) eq 'dg'`),