{"id":166793,"date":"2024-11-05T19:35:26","date_gmt":"2024-11-05T11:35:26","guid":{"rendered":"https:\/\/server.hk\/cnblog\/166793\/"},"modified":"2024-11-05T19:35:26","modified_gmt":"2024-11-05T11:35:26","slug":"%e4%ba%86%e8%a7%a3dcount%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8%e6%96%b9%e6%b3%95-dcount%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/166793\/","title":{"rendered":"\u4e86\u89e3Dcount\u6578\u64da\u5eab\u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5 (dcount\u6578\u64da\u5eab\u51fd\u6578)"},"content":{"rendered":"<h1 id=\"%e4%ba%86%e8%a7%a3dcount%e6%95%b8%e6%93%9a%e5%ba%ab%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8%e6%96%b9%e6%b3%95-ovVrUEagwl\">\u4e86\u89e3DCount\u6578\u64da\u5eab\u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5<\/h1>\n<p>DCount\u51fd\u6578\u662fMicrosoft Access\u548c\u5176\u4ed6\u4e00\u4e9b\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\u4e2d\u5e38\u7528\u7684\u4e00\u500b\u51fd\u6578\uff0c\u4e3b\u8981\u7528\u65bc\u8a08\u7b97\u7b26\u5408\u7279\u5b9a\u689d\u4ef6\u7684\u8a18\u9304\u6578\u91cf\u3002\u9019\u500b\u51fd\u6578\u5728\u6578\u64da\u5206\u6790\u548c\u5831\u544a\u751f\u6210\u4e2d\u975e\u5e38\u6709\u7528\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u5feb\u901f\u7372\u53d6\u6240\u9700\u7684\u6578\u64da\u7d71\u8a08\u4fe1\u606f\u3002\u672c\u6587\u5c07\u6df1\u5165\u63a2\u8a0eDCount\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5\u3001\u4f7f\u7528\u65b9\u6cd5\u53ca\u5176\u61c9\u7528\u7bc4\u4f8b\u3002<\/p>\n<h2 id=\"dcount%e5%87%bd%e6%95%b8%e7%9a%84%e5%9f%ba%e6%9c%ac%e8%aa%9e%e6%b3%95-ovVrUEagwl\">DCount\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5<\/h2>\n<p>DCount\u51fd\u6578\u7684\u57fa\u672c\u8a9e\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>DCount(expr, domain, [criteria])<\/code><\/pre>\n<ul>\n<li><strong>expr<\/strong>: \u8981\u8a08\u7b97\u7684\u5b57\u6bb5\u6216\u8868\u9054\u5f0f\u3002\u9019\u901a\u5e38\u662f\u6578\u64da\u5eab\u4e2d\u7684\u4e00\u500b\u5b57\u6bb5\u540d\u7a31\u3002<\/li>\n<li><strong>domain<\/strong>: \u8981\u67e5\u8a62\u7684\u6578\u64da\u4f86\u6e90\uff0c\u53ef\u4ee5\u662f\u8868\u540d\u6216\u67e5\u8a62\u540d\u3002<\/li>\n<li><strong>criteria<\/strong>: \u53ef\u9078\u53c3\u6578\uff0c\u7528\u65bc\u6307\u5b9a\u8a08\u7b97\u7684\u689d\u4ef6\u3002\u9019\u662f\u4e00\u500b\u5b57\u7b26\u4e32\uff0c\u5b9a\u7fa9\u4e86\u54ea\u4e9b\u8a18\u9304\u61c9\u8a72\u88ab\u8a08\u7b97\u3002<\/li>\n<\/ul>\n<h2 id=\"dcount%e5%87%bd%e6%95%b8%e7%9a%84%e4%bd%bf%e7%94%a8%e6%96%b9%e6%b3%95-ovVrUEagwl\">DCount\u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5<\/h2>\n<p>\u4f7f\u7528DCount\u51fd\u6578\u6642\uff0c\u9996\u5148\u9700\u8981\u78ba\u5b9a\u8981\u8a08\u7b97\u7684\u5b57\u6bb5\u548c\u6578\u64da\u4f86\u6e90\u3002\u63a5\u4e0b\u4f86\uff0c\u53ef\u4ee5\u6839\u64da\u9700\u8981\u6dfb\u52a0\u689d\u4ef6\u4f86\u7be9\u9078\u8a18\u9304\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u4f7f\u7528DCount\u51fd\u6578\u7684\u793a\u4f8b\uff1a<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b1%ef%bc%9a%e8%a8%88%e7%ae%97%e6%89%80%e6%9c%89%e8%a8%98%e9%8c%84%e7%9a%84%e6%95%b8%e9%87%8f-ovVrUEagwl\">\u793a\u4f8b1\uff1a\u8a08\u7b97\u6240\u6709\u8a18\u9304\u7684\u6578\u91cf<\/h3>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u8a08\u7b97\u540d\u70ba\u201cCustomers\u201d\u7684\u8868\u4e2d\u6240\u6709\u8a18\u9304\u7684\u6578\u91cf\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u78bc\uff1a<\/p>\n<pre><code>Dim totalCustomers As Integer\ntotalCustomers = DCount(\"*\", \"Customers\")\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0c\u4f7f\u7528\u4e86\u201c*\u201d\u4f5c\u70baexpr\uff0c\u8868\u793a\u8a08\u7b97\u6240\u6709\u8a18\u9304\u7684\u6578\u91cf\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b2%ef%bc%9a%e8%a8%88%e7%ae%97%e7%ac%a6%e5%90%88%e7%89%b9%e5%ae%9a%e6%a2%9d%e4%bb%b6%e7%9a%84%e8%a8%98%e9%8c%84%e6%95%b8%e9%87%8f-ovVrUEagwl\">\u793a\u4f8b2\uff1a\u8a08\u7b97\u7b26\u5408\u7279\u5b9a\u689d\u4ef6\u7684\u8a18\u9304\u6578\u91cf<\/h3>\n<p>\u5047\u8a2d\u6211\u5011\u60f3\u8981\u8a08\u7b97\u201cCustomers\u201d\u8868\u4e2d\u4f86\u81ea\u201c\u9999\u6e2f\u201d\u7684\u5ba2\u6236\u6578\u91cf\uff0c\u53ef\u4ee5\u9019\u6a23\u5beb\uff1a<\/p>\n<pre><code>Dim hkCustomers As Integer\nhkCustomers = DCount(\"*\", \"Customers\", \"City='\u9999\u6e2f'\")\n<\/code><\/pre>\n<p>\u9019\u88e1\uff0ccriteria\u53c3\u6578\u6307\u5b9a\u4e86\u53ea\u8a08\u7b97\u201cCity\u201d\u5b57\u6bb5\u70ba\u201c\u9999\u6e2f\u201d\u7684\u8a18\u9304\u3002<\/p>\n<h3 id=\"%e7%a4%ba%e4%be%8b3%ef%bc%9a%e8%a8%88%e7%ae%97%e7%89%b9%e5%ae%9a%e5%ad%97%e6%ae%b5%e7%9a%84%e5%94%af%e4%b8%80%e5%80%bc%e6%95%b8%e9%87%8f-ovVrUEagwl\">\u793a\u4f8b3\uff1a\u8a08\u7b97\u7279\u5b9a\u5b57\u6bb5\u7684\u552f\u4e00\u503c\u6578\u91cf<\/h3>\n<p>\u5982\u679c\u6211\u5011\u60f3\u8981\u8a08\u7b97\u201cOrders\u201d\u8868\u4e2d\u4e0d\u540c\u7522\u54c1\u7684\u6578\u91cf\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0b\u4ee3\u78bc\uff1a<\/p>\n<pre><code>Dim uniqueProducts As Integer\nuniqueProducts = DCount(\"ProductID\", \"Orders\", \"ProductID IS NOT NULL\")\n<\/code><\/pre>\n<p>\u5728\u9019\u500b\u4f8b\u5b50\u4e2d\uff0cexpr\u6307\u5b9a\u4e86\u201cProductID\u201d\u5b57\u6bb5\uff0c\u4e26\u4e14criteria\u78ba\u4fdd\u53ea\u8a08\u7b97\u4e0d\u70baNULL\u7684\u8a18\u9304\u3002<\/p>\n<h2 id=\"dcount%e5%87%bd%e6%95%b8%e7%9a%84%e6%b3%a8%e6%84%8f%e4%ba%8b%e9%a0%85-ovVrUEagwl\">DCount\u51fd\u6578\u7684\u6ce8\u610f\u4e8b\u9805<\/h2>\n<p>\u5728\u4f7f\u7528DCount\u51fd\u6578\u6642\uff0c\u6709\u5e7e\u9ede\u9700\u8981\u6ce8\u610f\uff1a<\/p>\n<ul>\n<li>\u6027\u80fd\uff1a\u5728\u5927\u578b\u6578\u64da\u96c6\u4e0a\u4f7f\u7528DCount\u53ef\u80fd\u6703\u5f71\u97ff\u6027\u80fd\uff0c\u56e0\u70ba\u5b83\u9700\u8981\u904d\u6b77\u6574\u500b\u6578\u64da\u96c6\u4f86\u8a08\u7b97\u7b26\u5408\u689d\u4ef6\u7684\u8a18\u9304\u3002<\/li>\n<li>\u689d\u4ef6\u683c\u5f0f\uff1acriteria\u53c3\u6578\u7684\u683c\u5f0f\u5fc5\u9808\u6b63\u78ba\uff0c\u5426\u5247\u53ef\u80fd\u6703\u5c0e\u81f4\u932f\u8aa4\u6216\u4e0d\u6b63\u78ba\u7684\u7d50\u679c\u3002<\/li>\n<li>\u6578\u64da\u985e\u578b\uff1a\u78ba\u4fdd\u5728criteria\u4e2d\u4f7f\u7528\u6b63\u78ba\u7684\u6578\u64da\u985e\u578b\uff0c\u7279\u5225\u662f\u5728\u6bd4\u8f03\u5b57\u7b26\u4e32\u548c\u6578\u5b57\u6642\u3002<\/li>\n<\/ul>\n<h2 id=\"%e7%b8%bd%e7%b5%90-ovVrUEagwl\">\u7e3d\u7d50<\/h2>\n<p>DCount\u51fd\u6578\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u80fd\u5920\u5e6b\u52a9\u7528\u6236\u5feb\u901f\u8a08\u7b97\u6578\u64da\u5eab\u4e2d\u7b26\u5408\u7279\u5b9a\u689d\u4ef6\u7684\u8a18\u9304\u6578\u91cf\u3002\u901a\u904e\u6b63\u78ba\u4f7f\u7528DCount\u51fd\u6578\uff0c\u60a8\u53ef\u4ee5\u63d0\u9ad8\u6578\u64da\u5206\u6790\u7684\u6548\u7387\uff0c\u4e26\u7372\u5f97\u66f4\u6e96\u78ba\u7684\u5831\u544a\u7d50\u679c\u3002\u5982\u679c\u60a8\u9700\u8981\u66f4\u9ad8\u6548\u7684\u6578\u64da\u8655\u7406\u548c\u5b58\u5132\u89e3\u6c7a\u65b9\u6848\uff0c\u8003\u616e\u4f7f\u7528<a href=\"https:\/\/server.hk\">\u9999\u6e2fVPS<\/a>\u6216<a href=\"https:\/\/server.hk\">\u96f2\u4f3a\u670d\u5668<\/a>\u4f86\u652f\u6301\u60a8\u7684\u696d\u52d9\u9700\u6c42\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e86\u89e3Dcount\u6578\u64da\u5eab\u51fd\u6578\u7684\u4f7f\u7528\u65b9\u6cd5\uff0c\u638c\u63e1\u5982\u4f55\u8a08\u7b97\u6578\u64da\u5eab\u4e2d\u7b26\u5408\u689d\u4ef6\u7684\u8a18\u9304\u6578\uff0c\u63d0\u5347\u6578\u64da\u5206\u6790\u6548\u7387\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-166793","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/166793","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=166793"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/166793\/revisions"}],"predecessor-version":[{"id":166794,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/166793\/revisions\/166794"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=166793"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=166793"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=166793"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}