<p class="intro">如果 f1 为空 就是用 f2 ，这就是 IFNULL MySQL SELECT * FROM 用户表 ORDER BY IFNULL(nickname, realname);SELECT IFNULL(NULL,10); -- 10</p> 如果 f1 为空 就是用 f2 ，这就是 IFNULL <br> MySQL <style> .CodeEntity .code_pieces ul.piece_anchor{width:25px;position:absolute;top:25px;left:-30px;z-index:1000;} .CodeEntity .code_pieces ul.piece_anchor li{width:25px;background: #efe;margin-bottom:2px;} .CodeEntity .code_pieces ul.piece_anchor li{border-left:3px #40AA63 solid;border-right:3px #efe solid;} .CodeEntity .code_pieces ul.piece_anchor li:hover{border-right:3px #40AA63 solid;border-left:3px #efe solid;} .CodeEntity .code_pieces ul.piece_anchor li a{color: #333;padding: 3px 10px;} .CodeEntity .code_pieces .jump_to_code{visibility:hidden;position:relative;} .CodeEntity .code_pieces .code_piece:hover .jump_to_code{visibility:visible;} .CodeEntity .code_pieces .code_piece:hover .jump_to_code a{text-decoration:none;} .CodeEntity .code_pieces h2 i{float:right;font-style:normal;font-weight:normal;} .CodeEntity .code_pieces h2 i a{font-size:9pt;background: #FFFFFF;color:#00A;padding: 2px 5px;text-decoration:none;} </style> <!--<ul class="piece_anchor">--> <!--<li>$velocityCount</li>--> <!--</ul>--> <div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush: sql; auto-links: false; ">SELECT * FROM 用户表 ORDER BY IFNULL(nickname, realname); SELECT IFNULL(NULL,10); -- > 10</pre><div class="contentsignin">登录后复制</div></div>
