{"id":47825,"date":"2023-12-11T15:13:10","date_gmt":"2023-12-11T07:13:10","guid":{"rendered":"https:\/\/wx.kaifamiao.info\/?p=47825"},"modified":"2023-12-11T15:13:10","modified_gmt":"2023-12-11T07:13:10","slug":"null%e6%98%af%e4%bb%80%e4%b9%88%e6%84%8f%e6%80%9d-4","status":"publish","type":"post","link":"http:\/\/wx.kaifamiao.info\/index.php\/2023\/12\/11\/null%e6%98%af%e4%bb%80%e4%b9%88%e6%84%8f%e6%80%9d-4\/","title":{"rendered":"NULL\u662f\u4ec0\u4e48\u610f\u601d?"},"content":{"rendered":"<p>&#8220;`&#8221;<\/p>\n<p>NULL(\u7a7a)\u8fd9\u4e2a\u503c\u662f\u6570\u636e\u5e93\u4e16\u754c\u91cc\u4e00\u4e2a\u975e\u5e38\u96be\u7f20\u7684\u4e1c\u897f\uff0c\u6240\u4ee5\u6709\u4e0d\u5c11\u5e94\u8058\u8005\u4f1a\u5728\u8fd9\u4e2a\u95ee\u9898\u4e0a\u8dcc\u8ddf\u5934\u60a8\u4e5f\u4e0d\u8981\u89c9\u5f97\u610f\u5916\u3002<br \/>\nNULL\u8fd9\u4e2a\u503c\u8868\u793aUNKNOWN(\u672a\u77e5):\u5b83\u4e0d\u8868\u793a\u201c\u201d(\u7a7a\u5b57\u7b26\u4e32)\u3002\u5047\u8bbe\u60a8\u7684SQL<br \/>\nServer\u6570\u636e\u5e93\u91cc\u6709ANSI_NULLS\uff0c\u5f53\u7136\u5728\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u4f1a\u6709\uff0c\u5bf9NULL\u8fd9\u4e2a\u503c\u7684\u4efb\u4f55\u6bd4\u8f83\u90fd\u4f1a\u751f\u4ea7\u4e00\u4e2aNULL\u503c\u3002\u60a8\u4e0d\u80fd\u628a\u4efb\u4f55\u503c\u4e0e\u4e00\u4e2a<br \/>\nUNKNOWN\u503c\u8fdb\u884c\u6bd4\u8f83\uff0c\u5e76\u5728\u903b\u8f91\u4e0a\u5e0c\u671b\u83b7\u5f97\u4e00\u4e2a\u7b54\u6848\u3002\u60a8\u5fc5\u987b\u4f7f\u7528IS NULL\u64cd\u4f5c\u7b26\u3002<\/p>\n<p>&lt;pre&gt;&lt;code&gt;            &quot;&#8220;`<br \/>\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"<p>&#8220;`&#8221; NULL(\u7a7a)\u8fd9\u4e2a\u503c\u662f\u6570\u636e\u5e93\u4e16\u754c\u91cc\u4e00\u4e2a\u975e\u5e38\u96be\u7f20\u7684\u4e1c\u897f\uff0c\u6240\u4ee5\u6709\u4e0d\u5c11\u5e94\u8058\u8005\u4f1a\u5728\u8fd9\u4e2a [&hellip;]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-47825","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/47825","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=47825"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/47825\/revisions"}],"predecessor-version":[{"id":47826,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/47825\/revisions\/47826"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=47825"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=47825"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=47825"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}