{"id":2382,"date":"2025-03-04T20:45:53","date_gmt":"2025-03-04T12:45:53","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2382"},"modified":"2025-03-04T20:45:53","modified_gmt":"2025-03-04T12:45:53","slug":"sqlite-explain%ef%bc%88%e8%a7%a3%e9%87%8a%ef%bc%89%e4%ba%8c","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/04\/sqlite-explain%ef%bc%88%e8%a7%a3%e9%87%8a%ef%bc%89%e4%ba%8c\/","title":{"rendered":"SQLite Explain\uff08\u89e3\u91ca\uff09\u4e8c"},"content":{"rendered":"\n

\u9664\u4e86 EXPLAIN<\/code> \u548c EXPLAIN QUERY PLAN<\/code>\uff0cSQLite \u8fd8\u63d0\u4f9b\u4e86\u4e00\u4e9b\u5176\u4ed6\u7684\u5206\u6790\u5de5\u5177\u548c\u6982\u5ff5\uff0c\u5e2e\u52a9\u5f00\u53d1\u8005\u6df1\u5165\u4e86\u89e3\u67e5\u8be2\u6027\u80fd\uff0c\u5e76\u5bf9\u67e5\u8be2\u8fdb\u884c\u4f18\u5316\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u76f8\u5173\u7684\u5185\u5bb9\uff1a<\/p>\n\n\n\n

1. EXPLAIN \u548c EXPLAIN QUERY PLAN \u7684\u7ec6\u8282<\/strong><\/h3>\n\n\n\n
    \n
  • EXPLAIN<\/strong> \u8fd4\u56de\u7684\u8f93\u51fa\u4f1a\u663e\u793a\u6bcf\u4e2a\u64cd\u4f5c\u7684\u8be6\u7ec6\u6b65\u9aa4\uff0c\u5b83\u5305\u542b\u4e86\u66f4\u4f4e\u7ea7\u522b\u7684\u4fe1\u606f\uff0c\u6bd4\u5982\u64cd\u4f5c\u7684\u6307\u9488\u7b49\uff0c\u8f93\u51fa\u901a\u5e38\u66f4\u590d\u6742\uff0c\u9002\u7528\u4e8e\u5bf9 SQL \u6267\u884c\u7684\u6df1\u5165\u5206\u6790\u3002 \u4f8b\u5982\uff0c\u6267\u884c EXPLAIN<\/code> \u53ef\u80fd\u4f1a\u663e\u793a\u50cf\u8fd9\u6837\u7684\u4fe1\u606f\uff1a<\/li>\n<\/ul>\n\n\n\n
      0   0       0       0   0   0   SCAN TABLE users<\/code><\/pre>\n\n\n\n
    \u8fd9\u4e9b\u4fe1\u606f\u5bf9\u5f00\u53d1\u8005\u66f4\u6709\u6311\u6218\uff0c\u9700\u8981\u4e00\u5b9a\u7684\u7406\u89e3\u80fd\u529b\u6765\u89e3\u6790\u6bcf\u4e00\u5217\u3002<\/p>\n\n\n\n
      \n
    • EXPLAIN QUERY PLAN<\/strong> \u63d0\u4f9b\u4e86\u66f4\u9ad8\u5c42\u6b21\u7684\u8f93\u51fa\uff0c\u4e14\u901a\u5e38\u66f4\u6613\u4e8e\u9605\u8bfb\u3002\u5b83\u4e13\u6ce8\u4e8e\u67e5\u8be2\u7684\u6bcf\u4e2a\u6b65\u9aa4\uff0c\u5e76\u63cf\u8ff0\u6267\u884c\u7684\u987a\u5e8f\u3001\u4f7f\u7528\u7684\u7d22\u5f15\u3001\u626b\u63cf\u7684\u8868\u7b49\u3002<\/li>\n<\/ul>\n\n\n\n
      2. EXPLAIN<\/code> \u7684\u5e38\u89c1\u8f93\u51fa\u5b57\u6bb5<\/strong><\/h3>\n\n\n\n
      EXPLAIN<\/code> \u548c EXPLAIN QUERY PLAN<\/code> \u8f93\u51fa\u7684\u5b57\u6bb5\u53ef\u4ee5\u5e2e\u52a9\u6211\u4eec\u66f4\u597d\u5730\u7406\u89e3\u67e5\u8be2\u7684\u6267\u884c\u8fc7\u7a0b\uff1a<\/p>\n\n\n\n
        \n
      • ID<\/strong>\uff1a\u67e5\u8be2\u4e2d\u6bcf\u4e2a\u6b65\u9aa4\u7684\u552f\u4e00\u6807\u8bc6\u7b26\u3002\u6bcf\u4e2a\u6b65\u9aa4\u7684 ID<\/code> \u4f1a\u6309\u7167\u67e5\u8be2\u7684\u6267\u884c\u987a\u5e8f\u751f\u6210\u3002<\/li>\n\n\n\n
      • Parent<\/strong>\uff1a\u663e\u793a\u5f53\u524d\u6b65\u9aa4\u7684\u7236\u6b65\u9aa4 ID<\/code>\uff0c\u5982\u679c\u662f\u6839\u6b65\u9aa4\uff08\u5373\u67e5\u8be2\u7684\u7b2c\u4e00\u6b65\uff09\uff0c\u5219\u4e3a NULL<\/code>\u3002<\/li>\n\n\n\n
      • Detail<\/strong>\uff1a\u63cf\u8ff0\u8be5\u6b65\u9aa4\u7684\u8be6\u7ec6\u4fe1\u606f\uff0c\u5982\u8868\u626b\u63cf\u3001\u7d22\u5f15\u626b\u63cf\u3001\u8fde\u63a5\u7c7b\u578b\u7b49\u3002<\/li>\n\n\n\n
      • SelectID<\/strong>\uff1a\u8868\u793a\u6267\u884c\u67e5\u8be2\u7684\u5177\u4f53\u6b65\u9aa4\uff0c\u4f8b\u5982\u9009\u62e9\u8868\u3001\u7d22\u5f15\u7b49\u3002<\/li>\n\n\n\n
      • UseTemp<\/strong>\uff1a\u8868\u793a\u662f\u5426\u4f7f\u7528\u4e86\u4e34\u65f6\u8868\u3002<\/li>\n<\/ul>\n\n\n\n
        3. \u5177\u4f53\u7684\u6267\u884c\u6b65\u9aa4<\/strong><\/h3>\n\n\n\n
        \u5728 EXPLAIN QUERY PLAN<\/code> \u7684\u8f93\u51fa\u4e2d\uff0c\u4e00\u4e9b\u5e38\u89c1\u7684\u6267\u884c\u6b65\u9aa4\u5305\u62ec\uff1a<\/p>\n\n\n\n
          \n
        • SCAN TABLE<\/strong>\uff1a\u8868\u793a\u5bf9\u8868\u7684\u5168\u8868\u626b\u63cf\u3002\u901a\u5e38\u53d1\u751f\u5728\u6ca1\u6709\u5408\u9002\u7d22\u5f15\u65f6\u3002<\/li>\n\n\n\n
        • USE INDEX<\/strong>\uff1a\u8868\u793a\u67e5\u8be2\u4f7f\u7528\u4e86\u67d0\u4e2a\u7d22\u5f15\u6765\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\u3002<\/li>\n\n\n\n
        • SEARCH TABLE<\/strong>\uff1a\u8868\u793a\u5bf9\u8868\u8fdb\u884c\u641c\u7d22\uff0c\u901a\u5e38\u662f\u5728\u4f7f\u7528\u7d22\u5f15\u65f6\u53d1\u751f\u3002<\/li>\n\n\n\n
        • INDEXED BY<\/strong>\uff1a\u8868\u793a\u5728\u67e5\u8be2\u65f6\u660e\u786e\u6307\u5b9a\u4f7f\u7528\u67d0\u4e2a\u7d22\u5f15\u3002<\/li>\n\n\n\n
        • NO INDEX<\/strong>\uff1a\u8868\u793a\u67e5\u8be2\u6ca1\u6709\u4f7f\u7528\u7d22\u5f15\uff0c\u901a\u5e38\u610f\u5473\u7740\u67e5\u8be2\u901f\u5ea6\u8f83\u6162\u3002<\/li>\n<\/ul>\n\n\n\n
          4. \u591a\u8868\u8fde\u63a5\u7684\u6267\u884c\u8ba1\u5212<\/strong><\/h3>\n\n\n\n
          \u5f53\u6267\u884c\u591a\u8868\u8fde\u63a5\uff08JOIN<\/code>\uff09\u67e5\u8be2\u65f6\uff0cEXPLAIN QUERY PLAN<\/code> \u4f1a\u663e\u793a\u6bcf\u4e2a\u8868\u7684\u626b\u63cf\u987a\u5e8f\uff0c\u4ee5\u53ca\u8fde\u63a5\u7684\u7c7b\u578b\uff08\u5982\u5d4c\u5957\u5faa\u73af\u8fde\u63a5\u3001\u54c8\u5e0c\u8fde\u63a5\u7b49\uff09\u3002<\/p>\n\n\n\n
          \u4f8b\u5b50\uff1a<\/h4>\n\n\n\n
          EXPLAIN QUERY PLAN\nSELECT orders.id, users.username\nFROM orders\nJOIN users ON orders.user_id = users.id\nWHERE orders.total > 100;<\/code><\/pre>\n\n\n\n
          \u53ef\u80fd\u4f1a\u8fd4\u56de\u5982\u4e0b\u7684\u6267\u884c\u8ba1\u5212\uff1a<\/p>\n\n\n\n
          ID  | Parent | SelectID | Order | Detail\n----|--------|----------|-------|----------------------------------------\n0   | NULL   | 0        | 0     | SCAN TABLE orders\n1   | 0      | 0        | 0     | SEARCH TABLE users USING INDEX user_id_index<\/code><\/pre>\n\n\n\n
          \u8be5\u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212\u8868\u793a\uff1a\u9996\u5148\u626b\u63cf orders<\/code> \u8868\uff0c\u7136\u540e\u4f7f\u7528 user_id_index<\/code> \u7d22\u5f15\u6765\u641c\u7d22 users<\/code> \u8868\u3002<\/p>\n\n\n\n
          5. \u5982\u4f55\u89e3\u8bfb\u6267\u884c\u8ba1\u5212<\/strong><\/h3>\n\n\n\n
          \u901a\u8fc7 EXPLAIN QUERY PLAN<\/code> \u83b7\u53d6\u7684\u6267\u884c\u8ba1\u5212\uff0c\u4f60\u53ef\u4ee5\u5206\u6790\u67e5\u8be2\u7684\u6bcf\u4e00\u6b65\uff0c\u5c24\u5176\u662f\uff1a<\/p>\n\n\n\n
            \n
          • \u7d22\u5f15\u4f7f\u7528\u60c5\u51b5<\/strong>\uff1a\u67e5\u8be2\u662f\u5426\u4f7f\u7528\u4e86\u7d22\u5f15\uff1f\u4f7f\u7528\u4e86\u54ea\u4e2a\u7d22\u5f15\uff1f\u7d22\u5f15\u662f\u5426\u6709\u6548\uff1f<\/li>\n\n\n\n
          • \u8868\u626b\u63cf\u7c7b\u578b<\/strong>\uff1a\u662f\u5168\u8868\u626b\u63cf\u8fd8\u662f\u7d22\u5f15\u626b\u63cf\uff1f\u5168\u8868\u626b\u63cf\u901a\u5e38\u6548\u7387\u8f83\u4f4e\u3002<\/li>\n\n\n\n
          • \u8fde\u63a5\u7c7b\u578b<\/strong>\uff1a\u5982\u679c\u67e5\u8be2\u6d89\u53ca\u591a\u4e2a\u8868\u8fde\u63a5\uff0c\u8fde\u63a5\u7684\u7c7b\u578b\u548c\u987a\u5e8f\u4e5f\u4f1a\u5f71\u54cd\u6027\u80fd\u3002<\/li>\n<\/ul>\n\n\n\n
            6. \u67e5\u8be2\u4f18\u5316\u7684\u6280\u5de7<\/strong><\/h3>\n\n\n\n
            \u6839\u636e\u6267\u884c\u8ba1\u5212\uff0c\u4f60\u53ef\u4ee5\u91c7\u53d6\u4ee5\u4e0b\u63aa\u65bd\u6765\u4f18\u5316\u67e5\u8be2\uff1a<\/p>\n\n\n\n
              \n
            • \u6dfb\u52a0\u7d22\u5f15<\/strong>\uff1a\u5982\u679c\u67e5\u8be2\u672a\u80fd\u4f7f\u7528\u7d22\u5f15\uff0c\u53ef\u4ee5\u8003\u8651\u5728\u67e5\u8be2\u4e2d\u4f7f\u7528\u7684\u5217\u4e0a\u6dfb\u52a0\u7d22\u5f15\uff0c\u7279\u522b\u662f WHERE \u5b50\u53e5\u4e2d\u6d89\u53ca\u7684\u5217\u3002<\/li>\n\n\n\n
            • \u91cd\u5199\u67e5\u8be2<\/strong>\uff1a\u6709\u65f6\u901a\u8fc7\u8c03\u6574\u67e5\u8be2\u7684\u7ed3\u6784\uff08\u5982\u8c03\u6574\u8fde\u63a5\u987a\u5e8f\u3001\u51cf\u5c11\u5d4c\u5957\u67e5\u8be2\u7b49\uff09\u53ef\u4ee5\u8ba9\u67e5\u8be2\u66f4\u9ad8\u6548\u3002<\/li>\n\n\n\n
            • \u907f\u514d\u5168\u8868\u626b\u63cf<\/strong>\uff1a\u786e\u4fdd\u67e5\u8be2\u80fd\u591f\u5229\u7528\u7d22\u5f15\u8fdb\u884c\u626b\u63cf\uff0c\u907f\u514d\u4f7f\u7528\u5168\u8868\u626b\u63cf\uff0c\u5c24\u5176\u662f\u6570\u636e\u91cf\u8f83\u5927\u7684\u8868\u3002<\/li>\n\n\n\n
            • \u907f\u514d\u5728 WHERE \u5b50\u53e5\u4e2d\u4f7f\u7528\u590d\u6742\u7684\u8ba1\u7b97<\/strong>\uff1a\u67e5\u8be2\u4e2d\u7684\u8ba1\u7b97\u53ef\u80fd\u4f1a\u4f7f SQLite \u65e0\u6cd5\u4f7f\u7528\u7d22\u5f15\u3002<\/li>\n<\/ul>\n\n\n\n
              7. \u6267\u884c\u8ba1\u5212\u5b9e\u4f8b\u5206\u6790<\/strong><\/h3>\n\n\n\n
              \u793a\u4f8b 1\uff1a\u7b80\u5355\u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212<\/h4>\n\n\n\n
              EXPLAIN QUERY PLAN SELECT * FROM users WHERE username = 'John';<\/code><\/pre>\n\n\n\n
              \u6267\u884c\u8ba1\u5212\u53ef\u80fd\u8fd4\u56de\uff1a<\/p>\n\n\n\n
              ID  | Parent | SelectID | Order | Detail\n----|--------|----------|-------|------------------------------\n0   | NULL   | 0        | 0     | SEARCH TABLE users USING INDEX username_index<\/code><\/pre>\n\n\n\n
              \u8fd9\u8868\u793a SQLite \u4f7f\u7528\u4e86 username_index<\/code> \u7d22\u5f15\u6765\u67e5\u627e users<\/code> \u8868\u4e2d\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\u3002<\/p>\n\n\n\n
              \u793a\u4f8b 2\uff1a\u5305\u542b JOIN<\/code> \u7684\u67e5\u8be2<\/h4>\n\n\n\n
              EXPLAIN QUERY PLAN \nSELECT orders.id, users.username\nFROM orders\nJOIN users ON orders.user_id = users.id\nWHERE orders.total > 100;<\/code><\/pre>\n\n\n\n
              \u6267\u884c\u8ba1\u5212\u53ef\u80fd\u4f1a\u8fd4\u56de\uff1a<\/p>\n\n\n\n
              ID  | Parent | SelectID | Order | Detail\n----|--------|----------|-------|----------------------------------------\n0   | NULL   | 0        | 0     | SCAN TABLE orders\n1   | 0      | 0        | 0     | SEARCH TABLE users USING INDEX user_id_index<\/code><\/pre>\n\n\n\n
              \u8fd9\u8868\u660e\u67e5\u8be2\u5148\u626b\u63cf\u4e86 orders<\/code> \u8868\uff0c\u7136\u540e\u901a\u8fc7 user_id_index<\/code> \u7d22\u5f15\u67e5\u627e users<\/code> \u8868\u3002<\/p>\n\n\n\n
              8. \u603b\u7ed3<\/strong><\/h3>\n\n\n\n
              \u901a\u8fc7 EXPLAIN<\/code> \u548c EXPLAIN QUERY PLAN<\/code>\uff0c\u4f60\u53ef\u4ee5\u6df1\u5165\u4e86\u89e3 SQLite \u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212\uff0c\u4ece\u800c\u5bf9\u67e5\u8be2\u6027\u80fd\u8fdb\u884c\u4f18\u5316\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u5173\u952e\u70b9\uff1a<\/p>\n\n\n\n
                \n
              • EXPLAIN QUERY PLAN<\/strong> \u63d0\u4f9b\u4e86\u4e00\u4e2a\u66f4\u9ad8\u5c42\u6b21\u7684\u6267\u884c\u8ba1\u5212\uff0c\u6613\u4e8e\u7406\u89e3\u3002<\/li>\n\n\n\n
              • \u901a\u8fc7\u5206\u6790\u67e5\u8be2\u7684\u6267\u884c\u6b65\u9aa4\uff0c\u53ef\u4ee5\u8bc6\u522b\u54ea\u4e9b\u6b65\u9aa4\u4f1a\u5bfc\u81f4\u6027\u80fd\u74f6\u9888\uff08\u5982\u5168\u8868\u626b\u63cf\uff09\u3002<\/li>\n\n\n\n
              • \u4f7f\u7528 \u7d22\u5f15<\/strong> \u53ef\u4ee5\u663e\u8457\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\uff0c\u5c24\u5176\u662f\u5728\u5927\u578b\u8868\u4e2d\u3002<\/li>\n<\/ul>\n\n\n\n
                \u5408\u7406\u4f7f\u7528 EXPLAIN<\/code> \u548c EXPLAIN QUERY PLAN<\/code> \u53ef\u4ee5\u5e2e\u52a9\u4f60\u4f18\u5316\u6570\u636e\u5e93\u67e5\u8be2\uff0c\u63d0\u5347\u5e94\u7528\u7a0b\u5e8f\u6027\u80fd\u3002\u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
                \u9664\u4e86 EXPLAIN \u548c EXPLAIN QUERY PLAN\uff0cSQLite \u8fd8\u63d0\u4f9b\u4e86\u4e00\u4e9b\u5176\u4ed6\u7684\u5206\u6790\u5de5\u5177\u548c\u6982\u5ff5 […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[76],"tags":[],"class_list":["post-2382","post","type-post","status-publish","format-standard","hentry","category-sqlite"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2382","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=2382"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2382\/revisions"}],"predecessor-version":[{"id":2383,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2382\/revisions\/2383"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2382"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2382"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2382"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}