{"id":2634,"date":"2025-03-11T23:45:09","date_gmt":"2025-03-11T15:45:09","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2634"},"modified":"2025-03-11T23:45:09","modified_gmt":"2025-03-11T15:45:09","slug":"postgresql-limit-%e5%ad%90%e5%8f%a5","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/11\/postgresql-limit-%e5%ad%90%e5%8f%a5\/","title":{"rendered":"PostgreSQL LIMIT \u5b50\u53e5"},"content":{"rendered":"\n

\u5728 PostgreSQL \u4e2d\uff0cLIMIT<\/code> \u5b50\u53e5\u7528\u4e8e\u9650\u5236\u67e5\u8be2\u7ed3\u679c\u7684\u884c\u6570\u3002\u5f53\u4f60\u53ea\u60f3\u4ece\u67e5\u8be2\u4e2d\u83b7\u53d6\u4e00\u5b9a\u6570\u91cf\u7684\u7ed3\u679c\u65f6\uff0c\u4f7f\u7528 LIMIT<\/code> \u975e\u5e38\u6709\u7528\uff0c\u5c24\u5176\u662f\u5728\u5904\u7406\u5927\u91cf\u6570\u636e\u65f6\uff0c\u53ef\u4ee5\u6709\u6548\u63d0\u9ad8\u67e5\u8be2\u7684\u6548\u7387\u3002<\/p>\n\n\n\n

1. LIMIT<\/code> \u5b50\u53e5\u7684\u57fa\u672c\u8bed\u6cd5<\/strong><\/h3>\n\n\n\n
SELECT column1, column2, ...\nFROM table_name\nWHERE condition\nLIMIT number;<\/code><\/pre>\n\n\n\n
    \n
  • number<\/code><\/strong>: \u8981\u8fd4\u56de\u7684\u7ed3\u679c\u884c\u6570\u3002<\/li>\n<\/ul>\n\n\n\n
    2. \u57fa\u672c\u793a\u4f8b<\/strong><\/h3>\n\n\n\n
    \u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a\u540d\u4e3a employees<\/code> \u7684\u8868\uff0c\u5305\u542b\u5458\u5de5\u4fe1\u606f\uff0c\u4ee5\u4e0b\u662f\u5982\u4f55\u4f7f\u7528 LIMIT<\/code> \u5b50\u53e5\u7684\u793a\u4f8b\uff1a<\/p>\n\n\n\n
    -- \u83b7\u53d6\u524d 5 \u4e2a\u5458\u5de5\u7684\u540d\u5b57\nSELECT name FROM employees LIMIT 5;<\/code><\/pre>\n\n\n\n
    \u8fd9\u6761\u67e5\u8be2\u5c06\u8fd4\u56de employees<\/code> \u8868\u4e2d\u524d 5 \u884c\u7684\u540d\u5b57\u3002<\/p>\n\n\n\n
    3. \u4e0e ORDER BY<\/code> \u5b50\u53e5\u7ed3\u5408\u4f7f\u7528<\/strong><\/h3>\n\n\n\n
    \u901a\u5e38\uff0cLIMIT<\/code> \u4e0e ORDER BY<\/code> \u5b50\u53e5\u4e00\u8d77\u4f7f\u7528\uff0c\u4ee5\u786e\u4fdd\u67e5\u8be2\u7ed3\u679c\u6309\u7279\u5b9a\u987a\u5e8f\u6392\u5217\u540e\uff0c\u518d\u9650\u5236\u8fd4\u56de\u7684\u884c\u6570\u3002\u4f8b\u5982\uff0c\u83b7\u53d6\u85aa\u6c34\u6700\u9ad8\u7684 3 \u540d\u5458\u5de5\uff1a<\/p>\n\n\n\n
    -- \u83b7\u53d6\u85aa\u6c34\u6700\u9ad8\u7684 3 \u540d\u5458\u5de5\nSELECT name, salary \nFROM employees \nORDER BY salary DESC \nLIMIT 3;<\/code><\/pre>\n\n\n\n
    4. \u4e0e OFFSET<\/code> \u5b50\u53e5\u7ed3\u5408\u4f7f\u7528<\/strong><\/h3>\n\n\n\n
    LIMIT<\/code> \u5b50\u53e5\u53ef\u4ee5\u4e0e OFFSET<\/code> \u5b50\u53e5\u4e00\u8d77\u4f7f\u7528\uff0c\u7528\u4e8e\u4ece\u67e5\u8be2\u7ed3\u679c\u7684\u7279\u5b9a\u4f4d\u7f6e\u5f00\u59cb\u8fd4\u56de\u6570\u636e\u3002OFFSET<\/code> \u7528\u4e8e\u8df3\u8fc7\u524d\u9762\u7684\u4e00\u4e9b\u884c\uff0cLIMIT<\/code> \u7528\u4e8e\u6307\u5b9a\u8fd4\u56de\u7684\u884c\u6570\u3002<\/p>\n\n\n\n
    -- \u8df3\u8fc7\u524d 5 \u884c\uff0c\u8fd4\u56de\u63a5\u4e0b\u6765\u7684 5 \u884c\nSELECT name FROM employees\nORDER BY name\nLIMIT 5 OFFSET 5;<\/code><\/pre>\n\n\n\n
    \u4e0a\u8ff0\u67e5\u8be2\u4f1a\u8df3\u8fc7 employees<\/code> \u8868\u4e2d\u7684\u524d 5 \u884c\uff0c\u5e76\u4ece\u7b2c 6 \u884c\u5f00\u59cb\u8fd4\u56de 5 \u884c\u6570\u636e\u3002<\/p>\n\n\n\n
    \u4f60\u4e5f\u53ef\u4ee5\u5c06 OFFSET<\/code> \u4e0e LIMIT<\/code> \u4e00\u8d77\u4f7f\u7528\uff0c\u7c7b\u4f3c\u4e8e\u5206\u9875\u67e5\u8be2\uff1a<\/p>\n\n\n\n
    -- \u83b7\u53d6\u7b2c 2 \u9875\u7684\u6570\u636e\uff0c\u6bcf\u9875\u663e\u793a 5 \u884c\nSELECT name FROM employees\nORDER BY name\nLIMIT 5 OFFSET 5;<\/code><\/pre>\n\n\n\n
    5. \u8d1f\u503c\u7684 OFFSET<\/code> \u548c LIMIT<\/code><\/strong><\/h3>\n\n\n\n
    \u5728 PostgreSQL \u4e2d\uff0cLIMIT<\/code> \u548c OFFSET<\/code> \u901a\u5e38\u662f\u975e\u8d1f\u6574\u6570\uff0c\u4f46\u4f60\u53ef\u4ee5\u4f7f\u7528\u8d1f\u503c\uff0c\u6765\u8868\u793a\u201c\u4e0d\u9650\u5236\u201d\uff1a<\/p>\n\n\n\n
    -- \u4e0d\u9650\u5236\u884c\u6570\uff0c\u8fd4\u56de\u6240\u6709\u6570\u636e\nSELECT name FROM employees LIMIT ALL;<\/code><\/pre>\n\n\n\n
    \u8fd9\u5c06\u8fd4\u56de\u67e5\u8be2\u7ed3\u679c\u4e2d\u7684\u6240\u6709\u884c\uff0c\u76f8\u5f53\u4e8e\u6ca1\u6709\u4f7f\u7528 LIMIT<\/code> \u5b50\u53e5\u3002<\/p>\n\n\n\n
    6. \u6027\u80fd\u8003\u8651<\/strong><\/h3>\n\n\n\n
      \n
    • LIMIT<\/code> \u5b50\u53e5\u7684\u4f7f\u7528\u4e0d\u4f1a\u5bfc\u81f4\u6570\u636e\u5e93\u626b\u63cf\u6240\u6709\u6570\u636e<\/strong>\uff0c\u5f53\u4e0e ORDER BY<\/code> \u4e00\u8d77\u4f7f\u7528\u65f6\uff0c\u6570\u636e\u5e93\u4ecd\u7136\u9700\u8981\u5bf9\u6570\u636e\u8fdb\u884c\u6392\u5e8f\u6216\u6392\u5e8f\u540e\u8fdb\u884c\u9650\u5236\uff0c\u56e0\u6b64\u5bf9\u4e8e\u6392\u5e8f\u5217\u6709\u7d22\u5f15\u65f6\uff0c\u67e5\u8be2\u7684\u6027\u80fd\u4f1a\u66f4\u597d\u3002<\/li>\n\n\n\n
    • \u5982\u679c\u6ca1\u6709\u7d22\u5f15\uff0c\u5e76\u4e14\u67e5\u8be2\u7684\u6570\u636e\u91cf\u975e\u5e38\u5927\uff0c\u4f7f\u7528 LIMIT<\/code> \u4ecd\u7136\u53ef\u80fd\u4f1a\u9020\u6210\u6027\u80fd\u95ee\u9898\uff0c\u5c24\u5176\u662f\u5728\u6ca1\u6709\u5408\u7406\u6392\u5e8f\u7684\u60c5\u51b5\u4e0b\u3002<\/li>\n<\/ul>\n\n\n\n
      7. \u4e0e DISTINCT<\/code> \u4e00\u8d77\u4f7f\u7528<\/strong><\/h3>\n\n\n\n
      LIMIT<\/code> \u5b50\u53e5\u4e5f\u53ef\u4ee5\u4e0e DISTINCT<\/code> \u5b50\u53e5\u7ed3\u5408\u4f7f\u7528\uff0c\u6765\u9650\u5236\u8fd4\u56de\u7684\u552f\u4e00\u503c\u7684\u6570\u91cf\u3002<\/p>\n\n\n\n
      -- \u83b7\u53d6\u4e0d\u540c\u7684\u85aa\u6c34\u503c\uff0c\u9650\u5236\u8fd4\u56de 3 \u4e2a\nSELECT DISTINCT salary \nFROM employees \nORDER BY salary DESC \nLIMIT 3;<\/code><\/pre>\n\n\n\n
      8. \u603b\u7ed3<\/strong><\/h3>\n\n\n\n
        \n
      • LIMIT<\/code> \u7528\u4e8e\u9650\u5236\u67e5\u8be2\u7ed3\u679c\u8fd4\u56de\u7684\u884c\u6570\u3002<\/li>\n\n\n\n
      • \u4f60\u53ef\u4ee5\u4f7f\u7528 LIMIT<\/code> \u5b50\u53e5\u76f4\u63a5\u9650\u5236\u8fd4\u56de\u884c\u6570\uff0c\u901a\u5e38\u4e0e ORDER BY<\/code> \u4e00\u8d77\u4f7f\u7528\uff0c\u4ee5\u63a7\u5236\u6570\u636e\u7684\u987a\u5e8f\u3002<\/li>\n\n\n\n
      • \u901a\u8fc7\u4f7f\u7528 OFFSET<\/code> \u5b50\u53e5\uff0c\u4f60\u53ef\u4ee5\u63a7\u5236\u7ed3\u679c\u96c6\u7684\u8d77\u59cb\u4f4d\u7f6e\uff0c\u5e38\u7528\u4e8e\u5206\u9875\u67e5\u8be2\u3002<\/li>\n\n\n\n
      • LIMIT<\/code> \u4e0e OFFSET<\/code> \u7684\u7ec4\u5408\u975e\u5e38\u9002\u5408\u5728\u5904\u7406\u5927\u91cf\u6570\u636e\u65f6\u8fdb\u884c\u5206\u9875\u663e\u793a\u3002<\/li>\n\n\n\n
      • LIMIT<\/code> \u5b50\u53e5\u975e\u5e38\u9002\u5408\u4ece\u5927\u6570\u636e\u96c6\u4e2d\u63d0\u53d6\u6837\u672c\u6216\u63a7\u5236\u8fd4\u56de\u7684\u884c\u6570\u3002<\/li>\n<\/ul>\n\n\n\n
        \u901a\u8fc7\u638c\u63e1 LIMIT<\/code> \u5b50\u53e5\uff0c\u80fd\u8ba9\u4f60\u66f4\u7075\u6d3b\u5730\u63a7\u5236\u67e5\u8be2\u7684\u7ed3\u679c\uff0c\u5c24\u5176\u5728\u5904\u7406\u5206\u9875\u6216\u5927\u91cf\u6570\u636e\u65f6\u66f4\u4e3a\u9ad8\u6548\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
        \u5728 PostgreSQL \u4e2d\uff0cLIMIT \u5b50\u53e5\u7528\u4e8e\u9650\u5236\u67e5\u8be2\u7ed3\u679c\u7684\u884c\u6570\u3002\u5f53\u4f60\u53ea\u60f3\u4ece\u67e5\u8be2\u4e2d\u83b7\u53d6\u4e00\u5b9a\u6570\u91cf\u7684\u7ed3\u679c\u65f6\uff0c\u4f7f […]<\/p>\n","protected":false},"author":1,"featured_media":2635,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[78],"tags":[],"class_list":["post-2634","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-postgresql"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2634","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/comments?post=2634"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2634\/revisions"}],"predecessor-version":[{"id":2636,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2634\/revisions\/2636"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media\/2635"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2634"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2634"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2634"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}