{"id":2159,"date":"2012-06-01T07:20:11","date_gmt":"2012-06-01T07:20:11","guid":{"rendered":"http:\/\/enjoyasp.net\/?p=2159"},"modified":"2012-06-01T07:20:11","modified_gmt":"2012-06-01T07:20:11","slug":"isnull%e7%9a%84%e9%99%b7%e9%98%b1","status":"publish","type":"post","link":"https:\/\/enjoyasp.net\/index.php\/2012\/06\/01\/isnull%e7%9a%84%e9%99%b7%e9%98%b1\/","title":{"rendered":"ISNULL\u7684\u9677\u9631"},"content":{"rendered":"<p>\n\tISNULL:<br \/>\n\tcheck_expression<\/p>\n<dl>\n<dd>\n<p>\n\t\t\t\u5c06\u88ab\u68c0\u67e5\u662f\u5426\u4e3a NULL \u7684<a href=\"ee53c5c8-e36c-40f9-8cd1-d933791b98fa.htm\">\u8868\u8fbe\u5f0f<\/a>\u3002check_expression \u53ef\u4ee5\u4e3a\u4efb\u4f55\u7c7b\u578b\u3002<\/p>\n<\/dd>\n<\/dl>\n<p>\n\treplacement_value<\/p>\n<dl>\n<dd>\n<p>\n\t\t\t\u5f53 check_expression \u4e3a NULL \u65f6\u8981\u8fd4\u56de\u7684\u8868\u8fbe\u5f0f\u3002replacement_value \u5fc5\u987b\u662f\u53ef\u4ee5<span style=\"font-size:28px;\"><strong>\u9690\u5f0f\u8f6c\u6362<\/strong><\/span>\u4e3a check_expresssion \u7c7b\u578b\u7684\u7c7b\u578b\u3002<\/p>\n<\/dd>\n<\/dl>\n<p>ISNULL:\u82e5\u524d\u4e00\u4e2a\u4e3aNULL,\u65f6\uff0c\u4f1a\u5c06\u540e\u4e00\u4e2a\u6309\u524d\u4e00\u4e2a\u6570\u636e\u7c7b\u578b\u8fdb\u884c\u8f6c\u6362\uff01<br \/>\n\u6d4b\u8bd5\uff1a<\/p>\n<pre class=\"brush:sql;first-line:1;pad-line-numbers:true;highlight:null;collapse:false;\">\r\nDECLARE @s VARCHAR(10),@result VARCHAR(50)\r\n           SET @result = REPLICATE(1,50)\r\n           SELECT LEN(@result)\r\n           SELECT LEN(ISNULL(@s,@result))\r\n\r\n<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>ISNULL: check_expression \u5c06\u88ab\u68c0\u67e5\u662f\u5426\u4e3a NULL \u7684\u8868\u8fbe\u5f0f\u3002check_expres [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36],"tags":[],"class_list":["post-2159","post","type-post","status-publish","format-standard","hentry","category-sql-server"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/posts\/2159","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/comments?post=2159"}],"version-history":[{"count":0,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/posts\/2159\/revisions"}],"wp:attachment":[{"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/media?parent=2159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/categories?post=2159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/enjoyasp.net\/index.php\/wp-json\/wp\/v2\/tags?post=2159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}