Add MIN/MAX LIMIT/OFFSET mention.

diff --git a/doc/FAQ b/doc/FAQ
index a60063eac184baed71c93e0a8ca82d5ebf413b6b..a1f9d150ba7a94ce3c77cc6c9cc685aaad18ad13 100644 (file)
--- a/doc/FAQ
+++ b/doc/FAQ
@@ -1,7 +1,7 @@
 
                 Frequently Asked Questions (FAQ) for PostgreSQL
                                        
-   Last updated: Thu Jun 20 22:00:57 EDT 2002
+   Last updated: Sun Jun 23 17:16:13 EDT 2002
    
    Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
    
@@ -723,7 +723,7 @@
    Indexes are not automatically used by every query. Indexes are only
    used if the table is larger than a minimum size, and the query selects
    only a small percentage of the rows in the table. This is because the
-   random disk access caused by an index scan is sometimes slower than a
+   random disk access caused by an index scan can be slower than a
    straight read through the table, or sequential scan.
    
    To determine if an index should be used, PostgreSQL must have
@@ -738,8 +738,14 @@
    sequential scan followed by an explicit sort is usually faster than an
    index scan of a large table.
    However, LIMIT combined with ORDER BY often will use an index because
-   only a small portion of the table is returned.
-   
+   only a small portion of the table is returned. In fact, though MAX()
+   and MIN() don't use indexes, it is possible to retrieve such values
+   using an index with ORDER BY and LIMIT:
+    SELECT col
+    FROM tab
+    ORDER BY col
+    LIMIT 1
+
    When using wild-card operators such as LIKE or ~, indexes can only be
    used if the beginning of the search is anchored to the start of the
    string. Therefore, to use indexes, LIKE patterns must not start with

diff --git a/doc/src/FAQ/FAQ.html b/doc/src/FAQ/FAQ.html
index 08e9c9d98ebb36ede10a6dd588383880aa2fa481..b6de1a6d49992973ac04c2ac8907224d73c1fa6b 100644 (file)
--- a/doc/src/FAQ/FAQ.html
+++ b/doc/src/FAQ/FAQ.html
@@ -14,7 +14,7 @@
   alink="#0000ff">
     <H1>Frequently Asked Questions (FAQ) for PostgreSQL</H1>
 
-    <P>Last updated: Thu Jun 20 22:00:57 EDT 2002</P>
+    <P>Last updated: Sun Jun 23 17:16:13 EDT 2002</P>
 
     <P>Current maintainer: Bruce Momjian (<A href=
     "mailto:pgman@candle.pha.pa.us">pgman@candle.pha.pa.us</A>)<BR>
@@ -923,7 +923,7 @@
     Indexes are not automatically used by every query. Indexes are only
     used if the table is larger than a minimum size, and the query
     selects only a small percentage of the rows in the table. This is
-    because the random disk access caused by an index scan is sometimes
+    because the random disk access caused by an index scan can be
     slower than a straight read through the table, or sequential scan. 
 
     <P>To determine if an index should be used, PostgreSQL must have
@@ -940,7 +940,15 @@
     usually faster than an index scan of a large table.</P>
     However, <SMALL>LIMIT</SMALL> combined with <SMALL>ORDER BY</SMALL>
     often will use an index because only a small portion of the table
-    is returned. 
+    is returned.  In fact, though MAX() and MIN() don't use indexes,
+    it is possible to retrieve such values using an index with ORDER BY
+    and LIMIT:
+<PRE>
+    SELECT col
+    FROM tab
+    ORDER BY col
+    LIMIT 1
+</PRE>
 
     <P>When using wild-card operators such as <SMALL>LIKE</SMALL> or
     <I>~</I>, indexes can only be used if the beginning of the search