diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index cf4ac7f7ac7055965c9c0abde3b614956c2edc6b..5e10ded524252662ad3d920663934557a560121c 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -1,4 +1,4 @@ -<!-- $Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.49 2001/01/21 22:02:01 petere Exp $ --> +<!-- $Header: /cvsroot/pgsql/doc/src/sgml/func.sgml,v 1.50 2001/02/05 19:21:45 petere Exp $ --> <chapter id="functions"> <title>Functions and Operators</title> @@ -185,6 +185,29 @@ <literal>3</literal>). </para> + <para> + In addition to the comparison operators, the special + <token>BETWEEN</token> construct is available. +<synopsis> +<replaceable>a</replaceable> BETWEEN <replaceable>x</replaceable> AND <replaceable>y</replaceable> +</synopsis> + is equivalent to +<synopsis> +<replaceable>a</replaceable> >= <replaceable>x</replaceable> AND <replaceable>a</replaceable> <= <replaceable>y</replaceable> +</synopsis> + Similarly, +<synopsis> +<replaceable>a</replaceable> NOT BETWEEN <replaceable>x</replaceable> AND <replaceable>y</replaceable> +</synopsis> + is equivalent to +<synopsis> +<replaceable>a</replaceable> < <replaceable>x</replaceable> OR <replaceable>a</replaceable> > <replaceable>y</replaceable> +</synopsis> + There is no difference between the two respective forms apart from + the <acronym>CPU</acronym> cycles required to rewrite the first one + into the second one internally. + </para> + <para> To check whether a value is or is not NULL, use the constructs <synopsis>