{"id":232,"date":"2025-07-10T15:26:04","date_gmt":"2025-07-10T07:26:04","guid":{"rendered":"https:\/\/blog.zeronely.cn\/?p=232"},"modified":"2025-07-10T15:26:05","modified_gmt":"2025-07-10T07:26:05","slug":"sql%e6%98%93%e9%94%99%e7%82%b9%e6%95%b4%e7%90%86","status":"publish","type":"post","link":"https:\/\/blog.zeronely.cn\/index.php\/2025\/07\/10\/sql%e6%98%93%e9%94%99%e7%82%b9%e6%95%b4%e7%90%86\/","title":{"rendered":"SQL\u6613\u9519\u70b9\u6574\u7406"},"content":{"rendered":"\n<p><strong>\u5173\u4e8eNULL<\/strong><\/p>\n\n\n\n<p>SQL \u91c7\u7528\u4e09\u503c\u903b\u8f91\uff08<code>TRUE<\/code>\u3001<code>FALSE<\/code> \u548c <code>UNKNOWN<\/code>\uff09\u3002\u4efb\u4f55\u6d89\u53ca <code>NULL<\/code> \u7684\u6bd4\u8f83\u6216\u903b\u8f91\u8fd0\u7b97\u7684\u7ed3\u679c\u90fd\u53ef\u80fd\u662f <code>UNKNOWN<\/code>\uff0c\u8fd9\u53ef\u80fd\u4f1a\u5f71\u54cd\u67e5\u8be2\u7ed3\u679c\u3002<\/p>\n\n\n\n<p>\u4f8b\u5982\uff1a<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/blog.zeronely.cn\/wp-content\/uploads\/2025\/07\/image-1.png'><img class=\"lazyload lazyload-style-1\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" decoding=\"async\" width=\"711\" height=\"126\" data-original=\"https:\/\/blog.zeronely.cn\/wp-content\/uploads\/2025\/07\/image-1.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" class=\"wp-image-233\"  sizes=\"auto, (max-width: 711px) 100vw, 711px\" \/><\/div><\/figure>\n\n\n\n<p>\u6240\u4ee5\uff0c\u8981\u5bf9null\u8fdb\u884c\u5904\u7406\uff0c\u9700\u8981\u4f7f\u7528is\u6216\u8005is not<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5173\u4e8eNULL SQL \u91c7\u7528\u4e09\u503c\u903b\u8f91\uff08TRUE\u3001FALSE \u548c UNKNOWN\uff09\u3002\u4efb\u4f55\u6d89\u53ca NULL \u7684\u6bd4\u8f83\u6216\u903b [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[11,1],"tags":[],"class_list":["post-232","post","type-post","status-publish","format-standard","hentry","category-11","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/posts\/232","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/comments?post=232"}],"version-history":[{"count":1,"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/posts\/232\/revisions"}],"predecessor-version":[{"id":234,"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/posts\/232\/revisions\/234"}],"wp:attachment":[{"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/media?parent=232"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/categories?post=232"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.zeronely.cn\/index.php\/wp-json\/wp\/v2\/tags?post=232"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}