From 4e58c7d7da236ce662633ea1fd7025b28b6d67be Mon Sep 17 00:00:00 2001
From: pengjunfeng11 <34857167+pengjunfeng11@users.noreply.github.com>
Date: Mon, 17 Mar 2025 10:47:17 +0800
Subject: [PATCH] Update postgres_impl.py

There is aBUG. When lighttrag uses the postgres@15 version, there will be an error.The BUG detail as follow:
PostgreSQL database, error:subquery in FROM must have an alias
HINT:  For example, FROM (SELECT ...) [AS] foo.
It roughly means that there is an error in SQL template, and you need to use the alias alias to declare the content of the subquery.
---
 lightrag/kg/postgres_impl.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lightrag/kg/postgres_impl.py b/lightrag/kg/postgres_impl.py
index 6a3e7c5f..99e4f5c4 100644
--- a/lightrag/kg/postgres_impl.py
+++ b/lightrag/kg/postgres_impl.py
@@ -1739,7 +1739,7 @@ SQL_TEMPLATES = {
                 FROM LIGHTRAG_VDB_ENTITY
                 where workspace=$1
                 AND chunk_id IN (SELECT chunk_id FROM relevant_chunks)
-            )
+            ) as chunk_distances
         WHERE distance>$2
         ORDER BY distance DESC
         LIMIT $3
@@ -1756,7 +1756,7 @@ SQL_TEMPLATES = {
                 FROM LIGHTRAG_DOC_CHUNKS
                 where workspace=$1
                 AND id IN (SELECT chunk_id FROM relevant_chunks)
-            )
+            ) as chunk_distances
             WHERE distance>$2
             ORDER BY distance DESC
             LIMIT $3