{"id":1719,"date":"2025-02-16T08:51:09","date_gmt":"2025-02-16T00:51:09","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=1719"},"modified":"2025-02-16T08:51:09","modified_gmt":"2025-02-16T00:51:09","slug":"sql-last-%e5%87%bd%e6%95%b0","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/02\/16\/sql-last-%e5%87%bd%e6%95%b0\/","title":{"rendered":"\u00a0SQL LAST() \u51fd\u6570"},"content":{"rendered":"\n

LAST()<\/code> \u51fd\u6570\u662f\u4e00\u4e2a\u975e\u6807\u51c6\u7684 SQL \u51fd\u6570\uff0c\u901a\u5e38\u7528\u4e8e\u8fd4\u56de\u67d0\u5217\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55<\/strong>\uff08\u6309\u6392\u5e8f\u89c4\u5219\uff09\u3002\u4f46\u662f\uff0cLAST()<\/code> \u5e76\u4e0d\u662f\u6240\u6709\u6570\u636e\u5e93\u7cfb\u7edf\u90fd\u652f\u6301\u7684 SQL \u6807\u51c6\u51fd\u6570\uff0c\u4e14\u5176\u652f\u6301\u7684\u6570\u636e\u5e93\u7cfb\u7edf\u8f83\u5c11\u3002\u4e0b\u9762\u6211\u5c06\u8be6\u7ec6\u4ecb\u7ecd LAST()<\/code> \u51fd\u6570\u7684\u7528\u9014\u3001\u5e38\u89c1\u95ee\u9898\u53ca\u5176\u89e3\u51b3\u65b9\u6cd5\u3002<\/p>\n\n\n\n

1. LAST()<\/code> \u51fd\u6570\u6982\u8ff0<\/strong><\/h3>\n\n\n\n
    \n
  • \u4f5c\u7528<\/strong>\uff1aLAST()<\/code> \u51fd\u6570\u7528\u4e8e\u8fd4\u56de\u67d0\u4e2a\u5217\u4e2d\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55<\/strong>\u3002\u901a\u5e38\uff0c\u5b83\u8fd4\u56de\u6309\u6307\u5b9a\u6392\u5e8f\u89c4\u5219\u6392\u5217\u540e\u7684\u6700\u540e\u4e00\u6761\u6570\u636e\u3002<\/li>\n\n\n\n
  • \u5e94\u7528\u573a\u666f<\/strong>\uff1a\u5e38\u7528\u4e8e\u67e5\u8be2\u67d0\u5217\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\uff0c\u6216\u8005\u8fd4\u56de\u6309\u67d0\u4e2a\u5b57\u6bb5\uff08\u5982\u65e5\u671f\uff09\u6392\u5e8f\u540e\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u3002<\/li>\n<\/ul>\n\n\n\n

    2. \u6570\u636e\u5e93\u652f\u6301\u60c5\u51b5<\/strong><\/h3>\n\n\n\n
      \n
    • \u652f\u6301\u7684\u6570\u636e\u5e93<\/strong>\uff1aLAST()<\/code> \u51fd\u6570\u5728\u4e00\u4e9b\u6570\u636e\u5e93\u7cfb\u7edf\u4e2d\u88ab\u652f\u6301\uff0c\u5982 MS Access<\/strong> \u548c SQLite<\/strong>\u3002<\/li>\n\n\n\n
    • \u4e0d\u652f\u6301\u7684\u6570\u636e\u5e93<\/strong>\uff1a\u4f8b\u5982 MySQL<\/strong>\u3001PostgreSQL<\/strong> \u548c SQL Server<\/strong> \u7b49\u4e0d\u652f\u6301 LAST()<\/code> \u51fd\u6570\u3002<\/li>\n<\/ul>\n\n\n\n

      3. LAST()<\/code> \u51fd\u6570\u7684\u8bed\u6cd5<\/strong><\/h3>\n\n\n\n

      \u5728 MS Access<\/strong> \u6216 SQLite<\/strong> \u7b49\u6570\u636e\u5e93\u4e2d\uff0cLAST()<\/code> \u51fd\u6570\u7684\u8bed\u6cd5\u901a\u5e38\u5982\u4e0b\uff1a<\/p>\n\n\n\n

      SELECT LAST(column_name)\nFROM table_name\nWHERE condition;<\/code><\/pre>\n\n\n\n
        \n
      • column_name<\/code>\uff1a\u4f60\u5e0c\u671b\u8fd4\u56de\u201c\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u201d\u7684\u5217\u3002<\/li>\n\n\n\n
      • table_name<\/code>\uff1a\u8868\u7684\u540d\u79f0\u3002<\/li>\n\n\n\n
      • condition<\/code>\uff1a\u53ef\u9009\u7684\u7b5b\u9009\u6761\u4ef6\u3002<\/li>\n<\/ul>\n\n\n\n
        4. \u793a\u4f8b\uff1a\u4f7f\u7528 LAST()<\/code> \u51fd\u6570<\/strong><\/h3>\n\n\n\n
        \u5047\u8bbe\u6709\u4e00\u4e2a\u5458\u5de5\u8868 employees<\/code>\uff0c\u8868\u7ed3\u6784\u5982\u4e0b\uff1a<\/p>\n\n\n\n
        employee_id<\/th>name<\/th>salary<\/th>hire_date<\/th><\/tr><\/thead>
        1<\/td>Tom<\/td>5000<\/td>2020-01-01<\/td><\/tr>
        2<\/td>Jane<\/td>6000<\/td>2021-01-01<\/td><\/tr>
        3<\/td>Bob<\/td>7000<\/td>2022-01-01<\/td><\/tr>
        4<\/td>Alice<\/td>8000<\/td>2023-01-01<\/td><\/tr>
        5<\/td>Mike<\/td>5500<\/td>2024-01-01<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
        \u83b7\u53d6\u5458\u5de5\u8868\u4e2d\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\uff08\u6309\u63d2\u5165\u987a\u5e8f\uff09\uff1a<\/h4>\n\n\n\n
        SELECT LAST(salary)\nFROM employees;<\/code><\/pre>\n\n\n\n
        \u8fd9\u4e2a\u67e5\u8be2\u5c06\u8fd4\u56de salary<\/code> \u5217\u4e2d\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\uff08\u6309\u8868\u4e2d\u7684\u884c\u987a\u5e8f\uff09\u3002<\/p>\n\n\n\n
        \u83b7\u53d6\u6309\u96c7\u4f63\u65e5\u671f\u6392\u5e8f\u540e\u7684\u6700\u540e\u4e00\u4f4d\u5458\u5de5\u7684\u85aa\u6c34\uff1a<\/h4>\n\n\n\n
        SELECT LAST(salary)\nFROM employees\nORDER BY hire_date DESC;<\/code><\/pre>\n\n\n\n
        \u8f93\u51fa<\/strong>\uff1a<\/p>\n\n\n\n
        last_salary<\/th><\/tr><\/thead>
        5500<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
        \u8fd9\u4e2a\u67e5\u8be2\u5c06\u6309 hire_date<\/code> \u964d\u5e8f\u6392\u5e8f\uff0c\u8fd4\u56de\u6700\u540e\u4e00\u4f4d\u96c7\u4f63\u7684\u5458\u5de5\u7684\u85aa\u6c34\u3002<\/p>\n\n\n\n
        5. \u5728\u4e0d\u652f\u6301 LAST()<\/code> \u7684\u6570\u636e\u5e93\u4e2d\u6a21\u62df<\/strong><\/h3>\n\n\n\n
        \u5bf9\u4e8e\u4e0d\u652f\u6301 LAST()<\/code> \u51fd\u6570\u7684\u6570\u636e\u5e93\uff08\u5982 MySQL<\/strong>\u3001PostgreSQL<\/strong>\u3001SQL Server<\/strong> \u7b49\uff09\uff0c\u4f60\u53ef\u4ee5\u4f7f\u7528\u5176\u4ed6\u65b9\u6cd5\u6765\u6a21\u62df LAST()<\/code> \u51fd\u6570\u7684\u6548\u679c\u3002\u901a\u5e38\u53ef\u4ee5\u901a\u8fc7 ORDER BY<\/code> \u548c LIMIT<\/code>\uff08\u6216 TOP<\/code>\uff09\u6765\u5b9e\u73b0\u3002<\/p>\n\n\n\n
        MySQL \/ PostgreSQL \u793a\u4f8b\uff1a<\/h4>\n\n\n\n
        SELECT salary\nFROM employees\nORDER BY hire_date DESC\nLIMIT 1;<\/code><\/pre>\n\n\n\n
          \n
        • LIMIT 1<\/code> \u7528\u4e8e\u83b7\u53d6\u6309 hire_date<\/code> \u964d\u5e8f\u6392\u5217\u540e\u7684\u7b2c\u4e00\u6761\u8bb0\u5f55\uff0c\u8fd9\u5373\u662f\u6700\u540e\u4e00\u4f4d\u96c7\u4f63\u7684\u5458\u5de5\u3002<\/li>\n<\/ul>\n\n\n\n
          SQL Server \u793a\u4f8b\uff1a<\/h4>\n\n\n\n
          SELECT TOP 1 salary\nFROM employees\nORDER BY hire_date DESC;<\/code><\/pre>\n\n\n\n
          6. LAST()<\/code> \u4e0e GROUP BY<\/code> \u7684\u4f7f\u7528<\/strong><\/h3>\n\n\n\n
          LAST()<\/code> \u51fd\u6570\u4e5f\u53ef\u4ee5\u4e0e GROUP BY<\/code> \u5b50\u53e5\u4e00\u8d77\u4f7f\u7528\uff0c\u5728\u67d0\u4e9b\u6570\u636e\u5e93\u4e2d\u53ef\u4ee5\u8fd4\u56de\u6bcf\u4e2a\u5206\u7ec4\u7684\u201c\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u201d\u3002\u4f8b\u5982\uff0c\u5047\u8bbe\u4f60\u6709\u4e00\u4e2a orders<\/code> \u8868\uff0c\u8bb0\u5f55\u4e86\u5ba2\u6237\u7684\u8ba2\u5355\u6570\u636e\uff0c\u6bcf\u4e2a\u8ba2\u5355\u6709\u4e00\u4e2a order_date<\/code> \u548c order_amount<\/code>\uff0c\u4f60\u5e0c\u671b\u83b7\u53d6\u6bcf\u4e2a\u5ba2\u6237\u7684\u6700\u540e\u4e00\u7b14\u8ba2\u5355\u91d1\u989d\u3002<\/p>\n\n\n\n
          MS Access \u793a\u4f8b\uff1a<\/h4>\n\n\n\n
          SELECT customer_id, LAST(order_amount)\nFROM orders\nGROUP BY customer_id;<\/code><\/pre>\n\n\n\n
          \u8be5\u67e5\u8be2\u4f1a\u8fd4\u56de\u6bcf\u4e2a\u5ba2\u6237\u7684\u6700\u540e\u4e00\u7b14\u8ba2\u5355\u91d1\u989d\uff0c\u6309\u5ba2\u6237\u5206\u7ec4\u3002<\/p>\n\n\n\n
          \u5982\u679c\u4f60\u7684\u6570\u636e\u5e93\u4e0d\u652f\u6301 LAST()<\/code>\uff0c\u53ef\u4ee5\u901a\u8fc7 ORDER BY<\/code> \u548c LIMIT<\/code> \u6216 TOP<\/code> \u6765\u5b9e\u73b0\u7c7b\u4f3c\u7684\u529f\u80fd\u3002<\/p>\n\n\n\n
          MySQL \/ PostgreSQL \u793a\u4f8b\uff1a<\/h4>\n\n\n\n
          SELECT customer_id, order_amount\nFROM orders\nWHERE order_date = (SELECT MAX(order_date) FROM orders WHERE customer_id = orders.customer_id)\nGROUP BY customer_id;<\/code><\/pre>\n\n\n\n
          7. \u5e38\u89c1\u95ee\u9898\u53ca\u89e3\u51b3\u65b9\u6848<\/strong><\/h3>\n\n\n\n
          1. LAST()<\/code> \u8fd4\u56de NULL<\/code><\/strong><\/h4>\n\n\n\n
            \n
          • \u95ee\u9898<\/strong>\uff1a\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u6ca1\u6709\u5339\u914d\u7684\u6570\u636e\uff0cLAST()<\/code> \u51fd\u6570\u4f1a\u8fd4\u56de NULL<\/code>\u3002<\/li>\n\n\n\n
          • \u89e3\u51b3\u65b9\u6848<\/strong>\uff1a\u786e\u4fdd\u67e5\u8be2\u6761\u4ef6\u6b63\u786e\uff0c\u5e76\u4e14\u8868\u4e2d\u6709\u6570\u636e\u3002\u5982\u679c\u9700\u8981\u5904\u7406 NULL<\/code>\uff0c\u53ef\u4ee5\u4f7f\u7528 COALESCE()<\/code> \u6216 IFNULL()<\/code> \u6765\u63d0\u4f9b\u9ed8\u8ba4\u503c\uff1a<\/li>\n<\/ul>\n\n\n\n
              SELECT COALESCE(LAST(salary), 0) AS last_salary\n  FROM employees;<\/code><\/pre>\n\n\n\n
            2. LAST()<\/code> \u8fd4\u56de\u7684\u7ed3\u679c\u4e0d\u7a33\u5b9a<\/strong><\/h4>\n\n\n\n
              \n
            • \u95ee\u9898<\/strong>\uff1aLAST()<\/code> \u8fd4\u56de\u7684\u7ed3\u679c\u53ef\u80fd\u4e0d\u7a33\u5b9a\uff0c\u7279\u522b\u662f\u5728\u6ca1\u6709\u660e\u786e\u6392\u5e8f\u7684\u60c5\u51b5\u4e0b\u3002<\/li>\n\n\n\n
            • \u89e3\u51b3\u65b9\u6848<\/strong>\uff1a\u59cb\u7ec8\u4f7f\u7528 ORDER BY<\/code> \u5b50\u53e5\u6765\u786e\u4fdd\u4f60\u83b7\u53d6\u7684\u662f\u6309\u7167\u4f60\u6307\u5b9a\u7684\u987a\u5e8f\u6392\u5217\u540e\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\uff1a<\/li>\n<\/ul>\n\n\n\n
                SELECT LAST(salary)\n  FROM employees\n  ORDER BY hire_date DESC;<\/code><\/pre>\n\n\n\n
              3. \u5728\u5206\u7ec4\u67e5\u8be2\u4e2d\u4f7f\u7528 LAST()<\/code> \u65f6\u51fa\u73b0\u95ee\u9898<\/strong><\/h4>\n\n\n\n
                \n
              • \u95ee\u9898<\/strong>\uff1a\u5982\u679c\u6ca1\u6709\u660e\u786e\u6392\u5e8f\uff0cLAST()<\/code> \u51fd\u6570\u53ef\u80fd\u4f1a\u8fd4\u56de\u610f\u5916\u7684\u7ed3\u679c\u3002<\/li>\n\n\n\n
              • \u89e3\u51b3\u65b9\u6848<\/strong>\uff1a\u786e\u4fdd\u5728 GROUP BY<\/code> \u67e5\u8be2\u4e2d\u4f7f\u7528 ORDER BY<\/code> \u6765\u786e\u4fdd\u6b63\u786e\u7684\u6392\u5e8f\uff1a<\/li>\n<\/ul>\n\n\n\n
                  SELECT customer_id, LAST(order_amount)\n  FROM orders\n  GROUP BY customer_id\n  ORDER BY order_date DESC;<\/code><\/pre>\n\n\n\n
                4. LAST()<\/code> \u548c DISTINCT<\/code> \u914d\u5408\u4f7f\u7528\u65f6\u7684\u95ee\u9898<\/strong><\/h4>\n\n\n\n
                  \n
                • \u95ee\u9898<\/strong>\uff1a\u5f53\u4f60\u4f7f\u7528 DISTINCT<\/code> \u548c LAST()<\/code> \u51fd\u6570\u4e00\u8d77\u65f6\uff0c\u53ef\u80fd\u4f1a\u5f97\u5230\u4e0d\u7b26\u5408\u9884\u671f\u7684\u7ed3\u679c\u3002<\/li>\n\n\n\n
                • \u89e3\u51b3\u65b9\u6848<\/strong>\uff1a\u907f\u514d\u5728 DISTINCT<\/code> \u67e5\u8be2\u4e2d\u76f4\u63a5\u4f7f\u7528 LAST()<\/code>\uff0c\u6216\u901a\u8fc7\u5176\u4ed6\u65b9\u5f0f\u91cd\u65b0\u7ec4\u7ec7\u67e5\u8be2\u903b\u8f91\uff0c\u786e\u4fdd\u83b7\u5f97\u6b63\u786e\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u3002<\/li>\n<\/ul>\n\n\n\n
                  8. \u603b\u7ed3<\/strong><\/h3>\n\n\n\n
                    \n
                  • LAST()<\/code> \u51fd\u6570\u652f\u6301\u7684\u6570\u636e\u5e93<\/strong>\uff1aMS Access\u3001SQLite \u7b49\uff0c\u4f46\u5927\u591a\u6570\u4e3b\u6d41\u6570\u636e\u5e93\uff08\u5982 MySQL\u3001PostgreSQL\u3001SQL Server\uff09\u5e76\u4e0d\u76f4\u63a5\u652f\u6301\u8be5\u51fd\u6570\u3002<\/li>\n\n\n\n
                  • \u5728\u4e0d\u652f\u6301 LAST()<\/code> \u7684\u6570\u636e\u5e93\u4e2d<\/strong>\uff1a\u53ef\u4ee5\u901a\u8fc7 ORDER BY<\/code> \u548c LIMIT<\/code>\uff08\u6216 TOP<\/code>\uff09\u6765\u83b7\u53d6\u6309\u67d0\u4e2a\u5b57\u6bb5\u6392\u5e8f\u540e\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u3002<\/li>\n\n\n\n
                  • \u6392\u5e8f\u95ee\u9898<\/strong>\uff1a\u4f7f\u7528 ORDER BY<\/code> \u5b50\u53e5\u786e\u4fdd\u7ed3\u679c\u662f\u6309\u9884\u671f\u7684\u987a\u5e8f\u6392\u5e8f\u540e\u83b7\u53d6\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\u3002<\/li>\n\n\n\n
                  • \u5206\u7ec4\u67e5\u8be2\u4e2d\u7684\u4f7f\u7528<\/strong>\uff1a\u5728\u5206\u7ec4\u67e5\u8be2\u4e2d\uff0c\u4f7f\u7528 LAST()<\/code> \u65f6\u52a1\u5fc5\u6307\u5b9a\u6392\u5e8f\u89c4\u5219\uff0c\u4ee5\u4fdd\u8bc1\u6b63\u786e\u7684\u8fd4\u56de\u7ed3\u679c\u3002<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
                    LAST() \u51fd\u6570\u662f\u4e00\u4e2a\u975e\u6807\u51c6\u7684 SQL \u51fd\u6570\uff0c\u901a\u5e38\u7528\u4e8e\u8fd4\u56de\u67d0\u5217\u7684\u6700\u540e\u4e00\u6761\u8bb0\u5f55\uff08\u6309\u6392\u5e8f\u89c4\u5219\uff09\u3002\u4f46\u662f\uff0cLAST( […]<\/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":[],"class_list":["post-1719","post","type-post","status-publish","format-standard","hentry","category-sql"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1719","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=1719"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1719\/revisions"}],"predecessor-version":[{"id":1720,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/1719\/revisions\/1720"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=1719"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=1719"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=1719"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}