{"id":115,"date":"2024-12-08T18:20:08","date_gmt":"2024-12-08T10:20:08","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=115"},"modified":"2024-12-08T18:20:08","modified_gmt":"2024-12-08T10:20:08","slug":"sql%e4%b8%ad%e7%9a%84%e5%88%86%e6%9e%90%e5%87%bd%e6%95%b0%e9%83%bd%e6%9c%89%e5%93%aa%e4%ba%9b%ef%bc%8c%e6%80%8e%e4%b9%88%e7%94%a8%e7%9a%84","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2024\/12\/08\/sql%e4%b8%ad%e7%9a%84%e5%88%86%e6%9e%90%e5%87%bd%e6%95%b0%e9%83%bd%e6%9c%89%e5%93%aa%e4%ba%9b%ef%bc%8c%e6%80%8e%e4%b9%88%e7%94%a8%e7%9a%84\/","title":{"rendered":"sql\u4e2d\u7684\u5206\u6790\u51fd\u6570\u90fd\u6709\u54ea\u4e9b\uff0c\u600e\u4e48\u7528\u7684"},"content":{"rendered":"\n
\n

SQL\u4e2d\u7684\u5206\u6790\u51fd\u6570\uff08\u7a97\u53e3\u51fd\u6570\uff09\u662f\u7528\u4e8e\u5728\u7ed3\u679c\u96c6\u4e2d\u6267\u884c\u590d\u6742\u7684\u8ba1\u7b97\u548c\u5206\u6790\u64cd\u4f5c\uff0c\u800c\u65e0\u9700\u6539\u53d8\u67e5\u8be2\u7684\u7ed3\u679c\u96c6\u7ed3\u6784\u3002\u5206\u6790\u51fd\u6570\u5728SQL\u4e2d\u975e\u5e38\u5f3a\u5927\uff0c\u5e38\u7528\u4e8e\u6392\u540d\u3001\u5206\u7ec4\u805a\u5408\u3001\u6ed1\u52a8\u7a97\u53e3\u8ba1\u7b97\u3001\u7d2f\u8ba1\u7b49\u573a\u666f\u3002<\/p>\n\n\n\n

\u4ee5\u4e0b\u662fSQL\u4e2d\u5e38\u89c1\u7684\u5206\u6790\u51fd\u6570\uff0c\u4ee5\u53ca\u5b83\u4eec\u7684\u4f7f\u7528\u65b9\u6cd5\uff1a<\/p>\n<\/blockquote>\n\n\n\n

\n\n\n\n

1. \u6392\u540d\u51fd\u6570<\/strong><\/h3>\n\n\n\n

\u6392\u540d\u51fd\u6570\u7528\u4e8e\u4e3a\u67e5\u8be2\u7ed3\u679c\u4e2d\u7684\u884c\u5206\u914d\u4e00\u4e2a\u6392\u540d\u3002<\/p>\n\n\n\n

1.1 ROW_NUMBER()<\/code><\/strong><\/h4>\n\n\n\n

ROW_NUMBER()<\/code> \u51fd\u6570\u4e3a\u7ed3\u679c\u96c6\u4e2d\u7684\u6bcf\u4e00\u884c\u5206\u914d\u4e00\u4e2a\u552f\u4e00\u7684\u884c\u53f7\u3002<\/p>\n\n\n\n

\u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n

SELECT \n    employee_id, \n    salary, \n    ROW_NUMBER() OVER (ORDER BY salary DESC) AS row_num\nFROM employees;<\/code><\/pre>\n\n\n\n
    \n
  • ORDER BY salary DESC<\/code><\/strong>\uff1a\u6839\u636e\u85aa\u8d44\u964d\u5e8f\u6392\u5217\uff0c\u4e3a\u6bcf\u4e2a\u5458\u5de5\u5206\u914d\u4e00\u4e2a\u552f\u4e00\u7684\u884c\u53f7\u3002<\/li>\n<\/ul>\n\n\n\n
    1.2 RANK()<\/code><\/strong><\/h4>\n\n\n\n
    RANK()<\/code> \u51fd\u6570\u4e3a\u7ed3\u679c\u96c6\u4e2d\u7684\u6bcf\u4e00\u884c\u5206\u914d\u4e00\u4e2a\u6392\u540d\uff0c\u76f8\u540c\u503c\u7684\u884c\u4f1a\u5171\u4eab\u76f8\u540c\u7684\u6392\u540d\uff0c\u540e\u7eed\u7684\u6392\u540d\u4f1a\u8df3\u8fc7\u3002<\/p>\n\n\n\n
    \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
    SELECT \n    employee_id, \n    salary, \n    RANK() OVER (ORDER BY salary DESC) AS rank\nFROM employees;<\/code><\/pre>\n\n\n\n
      \n
    • RANK()<\/code><\/strong> \u8ba1\u7b97\u85aa\u8d44\u6392\u540d\uff0c\u85aa\u8d44\u76f8\u540c\u7684\u5458\u5de5\u4f1a\u5171\u4eab\u76f8\u540c\u7684\u6392\u540d\uff0c\u540e\u7eed\u6392\u540d\u4f1a\u8df3\u8fc7\u3002<\/li>\n<\/ul>\n\n\n\n
      1.3 DENSE_RANK()<\/code><\/strong><\/h4>\n\n\n\n
      DENSE_RANK()<\/code> \u51fd\u6570\u7c7b\u4f3c\u4e8e RANK()<\/code>\uff0c\u4f46\u4e0d\u4f1a\u8df3\u8fc7\u6392\u540d\uff0c\u76f8\u540c\u7684\u503c\u4f1a\u5206\u914d\u76f8\u540c\u7684\u6392\u540d\uff0c\u4f46\u540e\u7eed\u7684\u6392\u540d\u662f\u8fde\u7eed\u7684\u3002<\/p>\n\n\n\n
      \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
      SELECT \n    employee_id, \n    salary, \n    DENSE_RANK() OVER (ORDER BY salary DESC) AS dense_rank\nFROM employees;<\/code><\/pre>\n\n\n\n
        \n
      • DENSE_RANK()<\/code><\/strong> \u8ba1\u7b97\u85aa\u8d44\u6392\u540d\uff0c\u85aa\u8d44\u76f8\u540c\u7684\u5458\u5de5\u4f1a\u5171\u4eab\u6392\u540d\uff0c\u540e\u7eed\u6392\u540d\u4e0d\u4f1a\u8df3\u8fc7\u3002<\/li>\n<\/ul>\n\n\n\n
        \n\n\n\n
        2. \u805a\u5408\u51fd\u6570<\/strong><\/h3>\n\n\n\n
        \u805a\u5408\u51fd\u6570\u53ef\u4ee5\u4e0e\u5206\u6790\u51fd\u6570\u4e00\u8d77\u4f7f\u7528\uff0c\u5bf9\u5206\u7ec4\u7684\u6570\u636e\u8fdb\u884c\u805a\u5408\u8ba1\u7b97\u3002<\/p>\n\n\n\n
        2.1 SUM()<\/code><\/strong><\/h4>\n\n\n\n
        SUM()<\/code> \u51fd\u6570\u7528\u4e8e\u8ba1\u7b97\u67d0\u4e2a\u5b57\u6bb5\u7684\u603b\u548c\u3002<\/p>\n\n\n\n
        \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
        SELECT \n    department_id, \n    employee_id, \n    salary, \n    SUM(salary) OVER (PARTITION BY department_id) AS department_salary\nFROM employees;<\/code><\/pre>\n\n\n\n
          \n
        • PARTITION BY department_id<\/code><\/strong>\uff1a\u6309\u90e8\u95e8\u5206\u7ec4\u8ba1\u7b97\u6bcf\u4e2a\u90e8\u95e8\u7684\u603b\u85aa\u8d44\u3002<\/li>\n<\/ul>\n\n\n\n
          2.2 AVG()<\/code><\/strong><\/h4>\n\n\n\n
          AVG()<\/code> \u51fd\u6570\u7528\u4e8e\u8ba1\u7b97\u67d0\u4e2a\u5b57\u6bb5\u7684\u5e73\u5747\u503c\u3002<\/p>\n\n\n\n
          \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
          SELECT \n    department_id, \n    AVG(salary) OVER (PARTITION BY department_id) AS avg_salary\nFROM employees;<\/code><\/pre>\n\n\n\n
            \n
          • \u8ba1\u7b97\u6bcf\u4e2a\u90e8\u95e8\u7684\u5e73\u5747\u85aa\u8d44\u3002<\/li>\n<\/ul>\n\n\n\n
            2.3 COUNT()<\/code><\/strong><\/h4>\n\n\n\n
            COUNT()<\/code> \u51fd\u6570\u7528\u4e8e\u8ba1\u7b97\u67d0\u4e2a\u5b57\u6bb5\u7684\u6570\u91cf\u3002<\/p>\n\n\n\n
            \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
            SELECT \n    department_id, \n    COUNT(employee_id) OVER (PARTITION BY department_id) AS department_count\nFROM employees;<\/code><\/pre>\n\n\n\n
              \n
            • \u8ba1\u7b97\u6bcf\u4e2a\u90e8\u95e8\u7684\u5458\u5de5\u6570\u91cf\u3002<\/li>\n<\/ul>\n\n\n\n
              \n\n\n\n
              3. \u6ed1\u52a8\u7a97\u53e3\u51fd\u6570<\/strong><\/h3>\n\n\n\n
              \u6ed1\u52a8\u7a97\u53e3\u51fd\u6570\u7528\u4e8e\u5728\u67e5\u8be2\u7ed3\u679c\u4e2d\u8ba1\u7b97\u524d\u540e\u67d0\u884c\u7684\u6570\u636e\uff0c\u5e38\u7528\u4e8e\u8ba1\u7b97\u7d2f\u8ba1\u503c\u6216\u6ed1\u52a8\u5e73\u5747\u3002<\/p>\n\n\n\n
              3.1 LEAD()<\/code><\/strong><\/h4>\n\n\n\n
              LEAD()<\/code> \u51fd\u6570\u8fd4\u56de\u5f53\u524d\u884c\u4e4b\u540e\u67d0\u4e00\u884c\u7684\u503c\uff0c\u5e38\u7528\u4e8e\u67e5\u770b\u540e\u7eed\u7684\u884c\u6570\u636e\u3002<\/p>\n\n\n\n
              \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
              SELECT \n    employee_id, \n    salary, \n    LEAD(salary, 1) OVER (ORDER BY salary DESC) AS next_salary\nFROM employees;<\/code><\/pre>\n\n\n\n
                \n
              • LEAD(salary, 1)<\/code><\/strong>\uff1a\u83b7\u53d6\u5f53\u524d\u884c\u4e4b\u540e1\u884c\u7684\u85aa\u8d44\u6570\u636e\u3002<\/li>\n<\/ul>\n\n\n\n
                3.2 LAG()<\/code><\/strong><\/h4>\n\n\n\n
                LAG()<\/code> \u51fd\u6570\u8fd4\u56de\u5f53\u524d\u884c\u4e4b\u524d\u67d0\u4e00\u884c\u7684\u503c\uff0c\u5e38\u7528\u4e8e\u67e5\u770b\u524d\u9762\u7684\u884c\u6570\u636e\u3002<\/p>\n\n\n\n
                \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
                SELECT \n    employee_id, \n    salary, \n    LAG(salary, 1) OVER (ORDER BY salary DESC) AS prev_salary\nFROM employees;<\/code><\/pre>\n\n\n\n
                  \n
                • LAG(salary, 1)<\/code><\/strong>\uff1a\u83b7\u53d6\u5f53\u524d\u884c\u4e4b\u524d1\u884c\u7684\u85aa\u8d44\u6570\u636e\u3002<\/li>\n<\/ul>\n\n\n\n
                  3.3 NTILE()<\/code><\/strong><\/h4>\n\n\n\n
                  NTILE(n)<\/code> \u51fd\u6570\u5c06\u6570\u636e\u5206\u6210n\u4e2a\u6876\uff0c\u8fd4\u56de\u6bcf\u4e00\u884c\u6240\u5728\u7684\u6876\u7f16\u53f7\u3002<\/p>\n\n\n\n
                  \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
                  SELECT \n    employee_id, \n    salary, \n    NTILE(4) OVER (ORDER BY salary DESC) AS quartile\nFROM employees;<\/code><\/pre>\n\n\n\n
                    \n
                  • NTILE(4)<\/code><\/strong>\uff1a\u5c06\u7ed3\u679c\u96c6\u5206\u4e3a4\u4e2a\u7ec4\uff0c\u6309\u85aa\u8d44\u964d\u5e8f\u6392\u5217\u3002<\/li>\n<\/ul>\n\n\n\n
                    \n\n\n\n
                    4. \u7a97\u53e3\u6846\u67b6\u51fd\u6570<\/strong><\/h3>\n\n\n\n
                    \u7a97\u53e3\u6846\u67b6\u7528\u4e8e\u6307\u5b9a\u7a97\u53e3\u7684\u8303\u56f4\uff0c\u63a7\u5236\u53c2\u4e0e\u5206\u6790\u7684\u6570\u636e\u884c\u3002<\/p>\n\n\n\n
                    4.1 ROWS BETWEEN<\/code><\/strong><\/h4>\n\n\n\n
                    ROWS BETWEEN<\/code> \u7528\u4e8e\u5b9a\u4e49\u5206\u6790\u7a97\u53e3\u7684\u524d\u540e\u8303\u56f4\u3002<\/p>\n\n\n\n
                    \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
                    SELECT \n    employee_id, \n    salary, \n    SUM(salary) OVER (ORDER BY salary ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING) AS window_sum\nFROM employees;<\/code><\/pre>\n\n\n\n
                      \n
                    • ROWS BETWEEN 1 PRECEDING AND 1 FOLLOWING<\/code><\/strong>\uff1a\u5305\u542b\u5f53\u524d\u884c\u7684\u524d\u4e00\u884c\u548c\u540e\u4e00\u884c\u7684\u6570\u636e\u3002<\/li>\n<\/ul>\n\n\n\n
                      4.2 RANGE BETWEEN<\/code><\/strong><\/h4>\n\n\n\n
                      RANGE BETWEEN<\/code> \u7528\u4e8e\u57fa\u4e8e\u6392\u5e8f\u5217\u7684\u8303\u56f4\u8ba1\u7b97\u3002<\/p>\n\n\n\n
                      \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
                      SELECT \n    employee_id, \n    salary, \n    SUM(salary) OVER (ORDER BY salary RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS running_total\nFROM employees;<\/code><\/pre>\n\n\n\n
                        \n
                      • RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW<\/code><\/strong>\uff1a\u4ece\u7b2c\u4e00\u884c\u5230\u5f53\u524d\u884c\u7684\u6240\u6709\u884c\u90fd\u53c2\u4e0e\u8ba1\u7b97\u3002<\/li>\n<\/ul>\n\n\n\n
                        \n\n\n\n
                        5. \u7279\u6b8a\u5206\u6790\u51fd\u6570<\/strong><\/h3>\n\n\n\n
                        \u4e00\u4e9b\u5206\u6790\u51fd\u6570\u7528\u4e8e\u83b7\u53d6\u7279\u5b9a\u7684\u884c\u503c\uff0c\u6bd4\u5982\u83b7\u53d6\u5206\u7ec4\u7684\u7b2c\u4e00\u4e2a\u6216\u6700\u540e\u4e00\u4e2a\u503c\u3002<\/p>\n\n\n\n
                        5.1 FIRST_VALUE()<\/code><\/strong><\/h4>\n\n\n\n
                        FIRST_VALUE()<\/code> \u51fd\u6570\u8fd4\u56de\u5206\u7ec4\u5185\u6392\u5e8f\u540e\u7684\u7b2c\u4e00\u884c\u6570\u636e\u3002<\/p>\n\n\n\n
                        \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
                        SELECT \n    department_id, \n    employee_id, \n    salary, \n    FIRST_VALUE(salary) OVER (PARTITION BY department_id ORDER BY salary DESC) AS highest_salary\nFROM employees;<\/code><\/pre>\n\n\n\n
                          \n
                        • \u83b7\u53d6\u6bcf\u4e2a\u90e8\u95e8\u85aa\u8d44\u6700\u9ad8\u7684\u5458\u5de5\u85aa\u8d44\u3002<\/li>\n<\/ul>\n\n\n\n
                          5.2 LAST_VALUE()<\/code><\/strong><\/h4>\n\n\n\n
                          LAST_VALUE()<\/code> \u51fd\u6570\u8fd4\u56de\u5206\u7ec4\u5185\u6392\u5e8f\u540e\u7684\u6700\u540e\u4e00\u884c\u6570\u636e\u3002<\/p>\n\n\n\n
                          \u7528\u6cd5\uff1a<\/strong><\/p>\n\n\n\n
                          SELECT \n    department_id, \n    employee_id, \n    salary, \n    LAST_VALUE(salary) OVER (PARTITION BY department_id ORDER BY salary DESC ROWS BETWEEN UNBOUNDED PRECEDING AND UNBOUNDED FOLLOWING) AS lowest_salary\nFROM employees;<\/code><\/pre>\n\n\n\n
                            \n
                          • \u83b7\u53d6\u6bcf\u4e2a\u90e8\u95e8\u85aa\u8d44\u6700\u4f4e\u7684\u5458\u5de5\u85aa\u8d44\u3002<\/li>\n<\/ul>\n\n\n\n
                            \n\n\n\n
                            \u603b\u7ed3<\/h3>\n\n\n\n
                            SQL\u5206\u6790\u51fd\u6570\uff08\u7a97\u53e3\u51fd\u6570\uff09\u63d0\u4f9b\u4e86\u5f3a\u5927\u7684\u6570\u636e\u5206\u6790\u80fd\u529b\uff0c\u5e38\u7528\u4e8e\uff1a<\/p>\n\n\n\n
                              \n
                            • \u6392\u540d\uff1aROW_NUMBER()<\/code>, RANK()<\/code>, DENSE_RANK()<\/code><\/li>\n\n\n\n
                            • \u805a\u5408\uff1aSUM()<\/code>, AVG()<\/code>, COUNT()<\/code><\/li>\n\n\n\n
                            • \u6ed1\u52a8\u7a97\u53e3\uff1aLEAD()<\/code>, LAG()<\/code>, NTILE()<\/code><\/li>\n\n\n\n
                            • \u7a97\u53e3\u6846\u67b6\uff1aROWS BETWEEN<\/code>, RANGE BETWEEN<\/code><\/li>\n\n\n\n
                            • \u7279\u6b8a\uff1aFIRST_VALUE()<\/code>, LAST_VALUE()<\/code><\/li>\n<\/ul>\n\n\n\n
                              \u4f7f\u7528\u5206\u6790\u51fd\u6570\u65f6\uff0c\u53ef\u4ee5\u7ed3\u5408 PARTITION BY<\/code>\uff08\u5206\u7ec4\uff09\u548c ORDER BY<\/code>\uff08\u6392\u5e8f\uff09\u6765\u7cbe\u7ec6\u63a7\u5236\u5206\u6790\u7684\u65b9\u5f0f\uff0c\u8fdb\u800c\u83b7\u5f97\u5f3a\u5927\u7684\u6570\u636e\u5206\u6790\u529f\u80fd\u3002<\/p>\n\n\n\n
                              <\/p>\n","protected":false},"excerpt":{"rendered":"
                              SQL\u4e2d\u7684\u5206\u6790\u51fd\u6570\uff08\u7a97\u53e3\u51fd\u6570\uff09\u662f\u7528\u4e8e\u5728\u7ed3\u679c\u96c6\u4e2d\u6267\u884c\u590d\u6742\u7684\u8ba1\u7b97\u548c\u5206\u6790\u64cd\u4f5c\uff0c\u800c\u65e0\u9700\u6539\u53d8\u67e5\u8be2\u7684\u7ed3\u679c\u96c6\u7ed3\u6784\u3002\u5206\u6790\u51fd\u6570\u5728 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36],"tags":[44,42,43],"class_list":["post-115","post","type-post","status-publish","format-standard","hentry","category-sql","tag-44","tag-42","tag-43"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/115","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=115"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/115\/revisions"}],"predecessor-version":[{"id":116,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/115\/revisions\/116"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=115"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=115"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=115"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}