function.pg-field-is-null.html
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Test if a field is SQL NULL</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.pg-fetch-row.html">pg_fetch_row</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.pg-field-name.html">pg_field_name</a></div> <div class="up"><a href="ref.pgsql.html">PostgreSQL Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.pg-field-is-null" class="refentry"> <div class="refnamediv"> <h1 class="refname">pg_field_is_null</h1> <p class="verinfo">(PHP 4 >= 4.2.0, PHP 5)</p><p class="refpurpose"><span class="refname">pg_field_is_null</span> — <span class="dc-title">Test if a field is SQL <i>NULL</i></span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">int</span> <span class="methodname"><b><b>pg_field_is_null</b></b></span> ( <span class="methodparam"><span class="type">resource</span> <tt class="parameter">$result</tt></span> , <span class="methodparam"><span class="type">int</span> <tt class="parameter">$row</tt></span> , <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <tt class="parameter">$field</tt></span> )</div> <div class="methodsynopsis dc-description"> <span class="type">int</span> <span class="methodname"><b><b>pg_field_is_null</b></b></span> ( <span class="methodparam"><span class="type">resource</span> <tt class="parameter">$result</tt></span> , <span class="methodparam"><span class="type"><a href="language.pseudo-types.html#language.types.mixed" class="type mixed">mixed</a></span> <tt class="parameter">$field</tt></span> )</div> <p class="para rdfs-comment"> <b>pg_field_is_null()</b> tests if a field in a PostgreSQL result resource is SQL <i>NULL</i> or not. </p> <blockquote><p><b class="note">Note</b>: This function used to be called <b>pg_fieldisnull()</b>. <br /> </p></blockquote> </div> <div class="refsect1 parameters"> <h3 class="title">Parameters</h3> <p class="para"> <dl> <dt> <span class="term"><i><tt class="parameter">result</tt></i></span> <dd> <p class="para"> PostgreSQL query result resource, returned by <a href="function.pg-query.html" class="function">pg_query()</a>, <a href="function.pg-query-params.html" class="function">pg_query_params()</a> or <a href="function.pg-execute.html" class="function">pg_execute()</a> (among others). </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">row</tt></i></span> <dd> <p class="para"> Row number in result to fetch. Rows are numbered from 0 upwards. If omitted, current row is fetched. </p> </dd> </dt> <dt> <span class="term"><i><tt class="parameter">field</tt></i></span> <dd> <p class="para"> Field number (starting from 0) as an <a href="language.types.integer.html" class="type integer">integer</a> or the field name as a <a href="language.types.string.html" class="type string">string</a>. </p> </dd> </dt> </dl> </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> Returns <i>1</i> if the field in the given row is SQL <i>NULL</i>, <i>0</i> if not. <b><tt>FALSE</tt></b> is returned if the row is out of range, or upon any other error. </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 <b>pg_field_is_null()</b> example</b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /> $dbconn </span><span style="color: #007700">= </span><span style="color: #0000BB">pg_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">"dbname=publisher"</span><span style="color: #007700">) or die (</span><span style="color: #DD0000">"Could not connect"</span><span style="color: #007700">);<br /> </span><span style="color: #0000BB">$res </span><span style="color: #007700">= </span><span style="color: #0000BB">pg_query</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbconn</span><span style="color: #007700">, </span><span style="color: #DD0000">"select * from authors where author = 'Orwell'"</span><span style="color: #007700">);<br /> if (</span><span style="color: #0000BB">$res</span><span style="color: #007700">) {<br /> if (</span><span style="color: #0000BB">pg_field_is_null</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #DD0000">"year"</span><span style="color: #007700">) == </span><span style="color: #0000BB">1</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"The value of the field year is null.\n"</span><span style="color: #007700">;<br /> }<br /> if (</span><span style="color: #0000BB">pg_field_is_null</span><span style="color: #007700">(</span><span style="color: #0000BB">$res</span><span style="color: #007700">, </span><span style="color: #0000BB">0</span><span style="color: #007700">, </span><span style="color: #DD0000">"year"</span><span style="color: #007700">) == </span><span style="color: #0000BB">0</span><span style="color: #007700">) {<br /> echo </span><span style="color: #DD0000">"The value of the field year is not null.\n"</span><span style="color: #007700">;<br /> }<br /> }<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div></div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.pg-fetch-row.html">pg_fetch_row</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.pg-field-name.html">pg_field_name</a></div> <div class="up"><a href="ref.pgsql.html">PostgreSQL Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
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