From c0c8a7235493cb2889eb9a31966ebddecea4616a Mon Sep 17 00:00:00 2001
From: "mintlify[bot]" <109931778+mintlify[bot]@users.noreply.github.com>
Date: Fri, 17 Apr 2026 22:14:46 +0000
Subject: [PATCH 1/2] Document multi-column join conditions in Sync Streams

Generated-By: mintlify-agent
---
 sync/streams/queries.mdx | 27 +++++++++++++++++++++++++++
 sync/supported-sql.mdx   |  3 +++
 2 files changed, 30 insertions(+)

diff --git a/sync/streams/queries.mdx b/sync/streams/queries.mdx
index 8e4838f4..3124186b 100644
--- a/sync/streams/queries.mdx
+++ b/sync/streams/queries.mdx
@@ -212,6 +212,33 @@ streams:
       WHERE gm2.user_id = auth.user_id()
 ```
 
+### Multi-column join conditions
+
+You can join two tables on multiple columns in the same `WHERE` clause. This is useful when a relationship is defined by a composite key — for example, matching on both a region and an ID:
+
+```yaml
+streams:
+  region_items:
+    query: |
+      SELECT a.* FROM a, b
+      WHERE a.region = b.region
+        AND a.item_id = b.item_id
+        AND b.user_id = auth.user_id()
+```
+
+This also works when chaining joins across several tables:
+
+```yaml
+streams:
+  linked_records:
+    query: |
+      SELECT a.* FROM a
+        JOIN b ON a.col1 = b.col1
+        JOIN c ON b.col2 = c.col2
+        JOIN d ON c.col3 = d.col3
+      WHERE d.col4 = a.col4
+```
+
 ### Join Limitations
 
 When writing stream queries with JOINs, keep in mind: use only `JOIN` or `INNER JOIN`; select columns from a single table (e.g. `comments.*`); and use simple equality conditions (`table1.column = table2.column`). For the full list of supported JOIN syntax and invalid examples, see [Supported SQL — JOIN syntax](/sync/supported-sql#join-syntax).
diff --git a/sync/supported-sql.mdx b/sync/supported-sql.mdx
index 9b5d91f8..4d355fbb 100644
--- a/sync/supported-sql.mdx
+++ b/sync/supported-sql.mdx
@@ -270,6 +270,9 @@ Sync Streams support a subset of join syntax. The following rules define what is
 -- Valid: columns from one table
 SELECT comments.* FROM comments INNER JOIN issues ON comments.issue_id = issues.id
 
+-- Valid: multiple equality conditions between tables (composite keys)
+SELECT a.* FROM a, b WHERE a.region = b.region AND a.item_id = b.item_id AND b.user_id = auth.user_id()
+
 -- Invalid: columns from multiple tables
 SELECT comments.*, issues.title FROM comments JOIN issues ON comments.issue_id = issues.id
 

From 7eb8baeb049a1c27ec0d2a7d93ff8959b0dd6493 Mon Sep 17 00:00:00 2001
From: Benita Volkmann <benita@journeyapps.com>
Date: Wed, 22 Apr 2026 16:43:23 +0200
Subject: [PATCH 2/2] Improve composite key example

---
 sync/streams/queries.mdx | 27 ---------------------------
 sync/supported-sql.mdx   |  7 +++++--
 2 files changed, 5 insertions(+), 29 deletions(-)

diff --git a/sync/streams/queries.mdx b/sync/streams/queries.mdx
index 3124186b..8e4838f4 100644
--- a/sync/streams/queries.mdx
+++ b/sync/streams/queries.mdx
@@ -212,33 +212,6 @@ streams:
       WHERE gm2.user_id = auth.user_id()
 ```
 
-### Multi-column join conditions
-
-You can join two tables on multiple columns in the same `WHERE` clause. This is useful when a relationship is defined by a composite key — for example, matching on both a region and an ID:
-
-```yaml
-streams:
-  region_items:
-    query: |
-      SELECT a.* FROM a, b
-      WHERE a.region = b.region
-        AND a.item_id = b.item_id
-        AND b.user_id = auth.user_id()
-```
-
-This also works when chaining joins across several tables:
-
-```yaml
-streams:
-  linked_records:
-    query: |
-      SELECT a.* FROM a
-        JOIN b ON a.col1 = b.col1
-        JOIN c ON b.col2 = c.col2
-        JOIN d ON c.col3 = d.col3
-      WHERE d.col4 = a.col4
-```
-
 ### Join Limitations
 
 When writing stream queries with JOINs, keep in mind: use only `JOIN` or `INNER JOIN`; select columns from a single table (e.g. `comments.*`); and use simple equality conditions (`table1.column = table2.column`). For the full list of supported JOIN syntax and invalid examples, see [Supported SQL — JOIN syntax](/sync/supported-sql#join-syntax).
diff --git a/sync/supported-sql.mdx b/sync/supported-sql.mdx
index 4d355fbb..74de319e 100644
--- a/sync/supported-sql.mdx
+++ b/sync/supported-sql.mdx
@@ -270,8 +270,11 @@ Sync Streams support a subset of join syntax. The following rules define what is
 -- Valid: columns from one table
 SELECT comments.* FROM comments INNER JOIN issues ON comments.issue_id = issues.id
 
--- Valid: multiple equality conditions between tables (composite keys)
-SELECT a.* FROM a, b WHERE a.region = b.region AND a.item_id = b.item_id AND b.user_id = auth.user_id()
+-- Valid: multiple equality conditions (composite keys)
+SELECT comments.* FROM comments, issues
+  WHERE comments.issue_id = issues.id
+    AND comments.region = issues.region
+    AND issues.user_id = auth.user_id()
 
 -- Invalid: columns from multiple tables
 SELECT comments.*, issues.title FROM comments JOIN issues ON comments.issue_id = issues.id