Apply proper sql.sgml change.

diff --git a/doc/src/sgml/sql.sgml b/doc/src/sgml/sql.sgml
index 6f0e4dcb21e89c170a2d4e09b2e3d4d679cfe21b..5a2ce9ab015c935810d0ada236482af1ce3517d3 100644 (file)
--- a/doc/src/sgml/sql.sgml
+++ b/doc/src/sgml/sql.sgml
@@ -1,5 +1,5 @@
 
 
  
@@ -1058,10 +1058,20 @@ select sname, pname from supplier
     item that occurs in a FROM clause and before any WHERE, GROUP BY,
     or HAVING clause.  Other table references, including table names or
     other JOIN clauses, may be included in the FROM clause if separated
-    by commas.  A JOIN of two tables is logically like any other
-    table listed in the FROM clause.  A JOINed table can only be JOINed
-    to additional tables in a Qualified JOIN as indicated by the
-    elipses below.
+    by commas.  JOINed tables are logically like any other
+    table listed in the FROM clause.
+    
+
+    
+    JOINs of all types can be chained together or nested where either or both of
+    T1 and
+    T2 may be JOINed tables.
+    A Qualified JOIN may be JOINed to another table (or JOINed table)
+    following its join specification, which consists of either an
+    ON search condition or
+    USING ( join column list ) clause.
+    Parenthesis can be used around JOIN clauses to control the order
+    of JOINs which are otherwise processed left to right.
     
 
     
@@ -1081,37 +1091,35 @@ select sname, pname from supplier
            respectively, and returns a joined table containing a cross
            product, NxM, of joined rows. For each row R1 of T1, each row
            R2 of T2 is joined with R1 to yield a joined table row JR
-           consisting of all fields in R1 and R2.
+           consisting of all fields in R1 and R2. A CROSS JOIN is
+           essentially an INNER JOIN ON TRUE.
            
            
        
 
        
-           Qualified JOINs            
+           Qualified JOINs
            
+
            
                 T1 
-               
-                   
-                    INNER 
+               
+                    INNER 
                    
-                       
-                       > LEFT 
-                       > RIGHT 
-                       > FULL 
+                        choice="req">
+                           > LEFT 
+                           > RIGHT 
+                           > FULL 
                        
-                        OUTER 
+                        choice="opt"> OUTER 
                    
-                   
-               
+               
                 JOIN 
                 T2 
-               
-                   
+               
                     ON search condition
                     USING ( join column list ) 
-                   
-               
+               
                 ... 
            
 
@@ -1122,9 +1130,6 @@ select sname, pname from supplier
            column names, which the joined tables must have in common, and joins
            the tables on those columns, resulting in a joined table having one
            column for each common column and all of the other columns from both tables.
-           Like all SELECT queries, the select list of the
-           SELECT query, before the FROM clause, decides which columns from the joined
-           table are in the result table returned.
            
 
            
@@ -1226,23 +1231,22 @@ select sname, pname from supplier
        
            NATURAL JOINs
            
+
            
                 T1 
-               
-                    NATURAL 
-                   
-                    INNER 
+                NATURAL 
+               
+                    INNER 
                    
-                       
-                       > LEFT 
-                       > RIGHT 
-                       > FULL 
+                        choice="req">
+                           > LEFT 
+                           > RIGHT 
+                           > FULL 
                        
-                        OUTER 
+                        choice="opt"> OUTER 
                    
-                   
-               
-                JOIN 
+               
+                JOIN                
                 T2 
            
 
@@ -1250,18 +1254,14 @@ select sname, pname from supplier
            A natural join creates a joined table where every pair of matching
            column names between the two tables are merged into one column. The
            join specification is effectively a USING clause containing all the
-            common column names and is otherwise like a Qualified JOIN except
-           additional JOINs to the JOINed table are not permitted.
+            common column names and is otherwise like a Qualified JOIN.
            
            
        
 
-       
-           UNION JOIN
-           Deprecated.
-       
     
 
+