From fd0b233c6b41a5bac0c9e3b1f4018d5da3f3878e Mon Sep 17 00:00:00 2001
From: wangdapeng <345731923@qq.com>
Date: Wed, 8 Apr 2026 08:56:37 +0800
Subject: [PATCH] doc: add introductory paragraphs to tutorial Chapters 2 and 3

---
 doc/src/sgml/advanced.sgml | 8 ++++++++
 doc/src/sgml/query.sgml    | 7 +++++++
 2 files changed, 15 insertions(+)

diff --git a/doc/src/sgml/advanced.sgml b/doc/src/sgml/advanced.sgml
index e15a332..c0c6d12 100644
--- a/doc/src/sgml/advanced.sgml
+++ b/doc/src/sgml/advanced.sgml
@@ -3,6 +3,14 @@
  <chapter id="tutorial-advanced">
   <title>Advanced Features</title>
 
+   <para>
+    This chapter builds on the basics covered earlier and introduces
+    several advanced <acronym>SQL</acronym> features in
+    <productname>PostgreSQL</productname>, including views, foreign keys,
+    transactions, window functions, and inheritance.
+   </para>
+
+
   <sect1 id="tutorial-advanced-intro">
    <title>Introduction</title>
 
diff --git a/doc/src/sgml/query.sgml b/doc/src/sgml/query.sgml
index b190f28..1c8b6ac 100644
--- a/doc/src/sgml/query.sgml
+++ b/doc/src/sgml/query.sgml
@@ -3,6 +3,13 @@
  <chapter id="tutorial-sql">
   <title>The <acronym>SQL</acronym> Language</title>
 
+   <para>
+    This chapter introduces fundamental <acronym>SQL</acronym> operations
+    in <productname>PostgreSQL</productname>, including creating tables,
+    populating them with data, and querying them.  It also covers joins
+    between tables, aggregate functions, and how to update and delete data.
+   </para>
+
   <sect1 id="tutorial-sql-intro">
    <title>Introduction</title>
 
-- 
2.46.2.windows.1