{"id":6281,"date":"2024-11-14T09:22:24","date_gmt":"2024-11-14T01:22:24","guid":{"rendered":"https:\/\/fwq.ai\/blog\/6281\/"},"modified":"2024-11-14T09:22:24","modified_gmt":"2024-11-14T01:22:24","slug":"sql%e8%af%ad%e5%8f%a5distinct%e7%9a%84%e6%80%8e%e4%b9%88%e7%94%a8","status":"publish","type":"post","link":"https:\/\/fwq.ai\/blog\/6281\/","title":{"rendered":"sql\u8bed\u53e5distinct\u7684\u600e\u4e48\u7528"},"content":{"rendered":"

\n sql \u4e2d\u7684 distinct \u5173\u952e\u5b57\u7528\u4e8e\u4ece\u67e5\u8be2\u7ed3\u679c\u4e2d\u5220\u9664\u91cd\u590d\u7684\u884c\u3002 \u5b83\u4fdd\u7559\u6bcf\u4e2a\u8868\u7684\u552f\u4e00\u884c\uff0c\u4e22\u5f03\u91cd\u590d\u503c\u3002\u4f7f\u7528\u65f6\uff0c\u5728 select \u8bed\u53e5\u5f00\u5934\u7d27\u8ddf\u5728\u7ed3\u679c\u5217\u540e\u9762\uff0c\u4f8b\u5982\uff1aselect distinct \u5217\u540d1, \u5217\u540d2 from \u8868\u540d; distinct \u7684\u597d\u5904\u5305\u62ec\u6d88\u9664\u91cd\u590d\u503c\uff0c\u7b80\u5316\u6570\u636e\u5206\u6790\uff0c\u63d0\u9ad8\u67e5\u8be2\u6027\u80fd\uff0c\u786e\u4fdd\u7ed3\u679c\u552f\u4e00\u6027\u3002\u4f46\u5b83\u4ec5\u5220\u9664\u91cd\u590d\u884c\uff0c\u4e0d\u5f71\u54cd\u884c\u5185\u5b57\u6bb5\u6392\u5e8f\uff0c\u5e76\u4e14\u53ef\u80fd\u5bfc\u81f4\u67e5\u8be2\u6027\u80fd\u4e0b\u964d\u3002\n<\/p><\/blockquote>\n

\"sql\u8bed\u53e5distinct\u7684\u600e\u4e48\u7528\u63d2\u56fe\"<\/p>\n

SQL \u4e2d DISTINCT \u5173\u952e\u5b57\u7684\u4f7f\u7528<\/strong><\/p>\n

\u4ec0\u4e48\u662f DISTINCT\uff1f<\/strong><\/p>\n

DISTINCT \u5173\u952e\u5b57\u7528\u4e8e\u4ece SQL \u67e5\u8be2\u7ed3\u679c\u4e2d\u5220\u9664\u91cd\u590d\u7684\u884c\u3002\u5b83\u4fdd\u7559\u67e5\u8be2\u4e2d\u6bcf\u4e2a\u8868\u7684\u552f\u4e00\u884c\uff0c\u800c\u4e22\u5f03\u91cd\u590d\u503c\u3002<\/p>\n

\u5982\u4f55\u4f7f\u7528 DISTINCT\uff1f<\/strong><\/p>\n

DISTINCT \u5173\u952e\u5b57\u7528\u4e8e SELECT \u8bed\u53e5\u7684\u5f00\u5934\uff0c\u7d27\u8ddf\u5728\u67e5\u8be2\u7ed3\u679c\u5217\u540e\u9762\uff1a<\/p>\n

SELECT DISTINCT \u5217\u540d1, \u5217\u540d2\nFROM \u8868\u540d;<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
\u4e3e\u4e2a\u4f8b\u5b50\uff1a<\/strong><\/p>\n
\u5047\u8bbe\u6709\u4ee5\u4e0b\u8868\uff1a<\/p>\n
| id | name |\n|---|---|\n| 1 | John |\n| 2 | Mary |\n| 3 | John |<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
\u4ee5\u4e0b\u67e5\u8be2\u4f7f\u7528 DISTINCT \u5173\u952e\u5b57\u5220\u9664\u91cd\u590d\u7684\u884c\uff1a<\/p>\n
SELECT DISTINCT name\nFROM \u8868\u540d;<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
\u8f93\u51fa\uff1a<\/strong><\/p>\n
| name |\n|---|---|\n| John |\n| Mary |<\/pre>\n
 \u767b\u5f55\u540e\u590d\u5236 <\/p>\n
DISTINCT \u7684\u597d\u5904\uff1a<\/strong><\/p>\n
\u4f7f\u7528 DISTINCT \u53ef\u4ee5\u7b80\u5316\u6570\u636e\u5206\u6790\uff0c\u56e0\u4e3a\u5b83\uff1a<\/p>\n
    \n
  • \u6d88\u9664\u91cd\u590d\u503c\uff0c\u4f7f\u7ed3\u679c\u66f4\u7b80\u6d01\u3002<\/li>\n
  • \u63d0\u9ad8\u67e5\u8be2\u6027\u80fd\uff0c\u56e0\u4e3a\u6570\u636e\u5e93\u4e0d\u5fc5\u5904\u7406\u91cd\u590d\u7684\u6570\u636e\u3002<\/li>\n
  • \u786e\u4fdd\u7ed3\u679c\u4e2d\u4ec5\u5305\u542b\u552f\u4e00\u503c\u3002<\/li>\n<\/ul>\n
    \u6ce8\u610f\u4e8b\u9879\uff1a<\/strong><\/p>\n
      \n
    • DISTINCT \u4ec5\u5220\u9664\u91cd\u590d\u7684\u884c\uff0c\u4e0d\u5f71\u54cd\u884c\u5185\u5b57\u6bb5\u7684\u6392\u5e8f\u3002<\/li>\n
    • \u5982\u679c\u67e5\u8be2\u4e2d\u4e0d\u4f7f\u7528 ALL \u5173\u952e\u5b57\uff0cDISTINCT \u9ed8\u8ba4\u662f\u542f\u7528\u72b6\u6001\u3002<\/li>\n
    • \u5728\u67d0\u4e9b\u60c5\u51b5\u4e0b\uff0c\u4f7f\u7528 DISTINCT \u53ef\u80fd\u5bfc\u81f4\u67e5\u8be2\u6027\u80fd\u4e0b\u964d\uff0c\u56e0\u4e3a\u5b83\u9700\u8981\u5bf9\u6570\u636e\u8fdb\u884c\u989d\u5916\u7684\u5904\u7406\u3002<\/li>\n<\/ul>\n
      \u4ee5\u4e0a\u5c31\u662fdistinct\u7684\u600e\u4e48\u7528\u7684\u8be6\u7ec6\u5185\u5bb9\uff0c\u66f4\u591a\u8bf7\u5173\u6ce8\u7c73\u4e91\u7f51\u5176\u5b83\u76f8\u5173\u6587\u7ae0\uff01<\/p>\n","protected":false},"excerpt":{"rendered":"
      sql \u4e2d\u7684 distinct \u5173\u952e\u5b57\u7528\u4e8e\u4ece\u67e5\u8be2\u7ed3\u679c\u4e2d\u5220\u9664\u91cd\u590d\u7684\u884c\u3002 \u5b83\u4fdd\u7559\u6bcf\u4e2a\u8868\u7684\u552f\u4e00\u884c\uff0c\u4e22\u5f03\u91cd\u590d\u503c\u3002\u4f7f\u7528\u65f6\uff0c\u5728 select \u8bed\u53e5\u5f00\u5934\u7d27\u8ddf\u5728\u7ed3\u679c\u5217\u540e\u9762\uff0c\u4f8b\u5982\uff1aselect distinct \u5217\u540d1, \u5217\u540d2 from \u8868\u540d; distinct \u7684\u597d\u5904\u5305\u62ec\u6d88\u9664\u91cd\u590d\u503c\uff0c\u7b80\u5316\u6570\u636e\u5206\u6790\uff0c\u63d0\u9ad8\u67e5\u8be2\u6027\u80fd\uff0c\u786e\u4fdd\u7ed3\u679c\u552f\u4e00\u6027\u3002\u4f46\u5b83\u4ec5\u5220\u9664\u91cd\u590d\u884c\uff0c\u4e0d\u5f71\u54cd\u884c\u5185\u5b57\u6bb5\u6392\u5e8f\uff0c\u5e76\u4e14\u53ef\u80fd\u5bfc\u81f4\u67e5\u8be2\u6027\u80fd\u4e0b\u964d\u3002 SQL \u4e2d DISTINCT \u5173\u952e\u5b57\u7684\u4f7f\u7528 \u4ec0\u4e48\u662f DISTINCT\uff1f DISTINCT \u5173\u952e\u5b57\u7528\u4e8e\u4ece SQL \u67e5\u8be2\u7ed3\u679c\u4e2d\u5220\u9664\u91cd\u590d\u7684\u884c\u3002\u5b83\u4fdd\u7559\u67e5\u8be2\u4e2d\u6bcf\u4e2a\u8868\u7684\u552f\u4e00\u884c\uff0c\u800c\u4e22\u5f03\u91cd\u590d\u503c\u3002 \u5982\u4f55\u4f7f\u7528 DISTINCT\uff1f DISTINCT \u5173\u952e\u5b57\u7528\u4e8e SELECT \u8bed\u53e5\u7684\u5f00\u5934\uff0c\u7d27\u8ddf\u5728\u67e5\u8be2\u7ed3\u679c\u5217\u540e\u9762\uff1a SELECT DISTINCT \u5217\u540d1, \u5217\u540d2 FROM \u8868\u540d; \u767b\u5f55\u540e\u590d\u5236 \u4e3e\u4e2a\u4f8b\u5b50\uff1a \u5047\u8bbe\u6709\u4ee5\u4e0b\u8868\uff1a | id | name | |—|—| | 1 | John | | 2 | Mary | […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[16],"tags":[],"class_list":["post-6281","post","type-post","status-publish","format-standard","hentry","category-16"],"_links":{"self":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/6281","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/comments?post=6281"}],"version-history":[{"count":0,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/posts\/6281\/revisions"}],"wp:attachment":[{"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/media?parent=6281"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/categories?post=6281"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/fwq.ai\/blog\/wp-json\/wp\/v2\/tags?post=6281"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}