{"id":2352,"date":"2025-03-04T19:28:09","date_gmt":"2025-03-04T11:28:09","guid":{"rendered":"https:\/\/www.laixuexila.com\/?p=2352"},"modified":"2025-03-04T19:28:09","modified_gmt":"2025-03-04T11:28:09","slug":"sqlite-unions-%e5%ad%90%e5%8f%a5","status":"publish","type":"post","link":"https:\/\/www.laixuexila.com\/index.php\/2025\/03\/04\/sqlite-unions-%e5%ad%90%e5%8f%a5\/","title":{"rendered":"SQLite Unions \u5b50\u53e5"},"content":{"rendered":"\n
\n

\u5728 SQLite<\/strong> \u4e2d\uff0cUNION<\/code> \u5b50\u53e5\u7528\u4e8e\u5408\u5e76\u591a\u4e2a SELECT<\/code> \u8bed\u53e5\u7684\u7ed3\u679c<\/strong>\uff0c\u5e76\u8fd4\u56de\u53bb\u91cd\u540e\u7684\u7ed3\u679c<\/strong>\u3002\u5982\u679c\u4f60\u60f3\u5305\u542b\u91cd\u590d\u6570\u636e<\/strong>\uff0c\u53ef\u4ee5\u4f7f\u7528 UNION ALL<\/code>\u3002<\/p>\n<\/blockquote>\n\n\n\n

\n\n\n\n

1. UNION<\/code> \u8bed\u6cd5<\/strong><\/h2>\n\n\n\n
SELECT column1, column2 FROM table1\nUNION\nSELECT column1, column2 FROM table2;<\/code><\/pre>\n\n\n\n
    \n
  • UNION<\/code> \u9ed8\u8ba4\u53bb\u91cd<\/strong>\u91cd\u590d\u884c\u3002<\/li>\n\n\n\n
  • \u5217\u7684\u6570\u91cf\u548c\u6570\u636e\u7c7b\u578b\u5fc5\u987b\u5339\u914d\u3002<\/li>\n<\/ul>\n\n\n\n
    \n\n\n\n
    2. UNION<\/code> \u793a\u4f8b<\/strong><\/h2>\n\n\n\n
    \u793a\u4f8b\uff1a\u5408\u5e76\u4e24\u4e2a\u8868\u7684\u7528\u6237<\/strong><\/h3>\n\n\n\n
    CREATE TABLE users1 (\n    id INTEGER PRIMARY KEY,\n    name TEXT\n);\n\nCREATE TABLE users2 (\n    id INTEGER PRIMARY KEY,\n    name TEXT\n);\n\nINSERT INTO users1 VALUES (1, 'Alice'), (2, 'Bob');\nINSERT INTO users2 VALUES (2, 'Bob'), (3, 'Charlie');\n\nSELECT name FROM users1\nUNION\nSELECT name FROM users2;<\/code><\/pre>\n\n\n\n
    \u7ed3\u679c<\/strong><\/p>\n\n\n\n
    name\n-------\nAlice\nBob\nCharlie<\/code><\/pre>\n\n\n\n
      \n
    • Bob<\/code> \u5728 users1<\/code> \u548c users2<\/code> \u90fd\u51fa\u73b0\uff0c\u4f46 UNION<\/code> \u53ea\u8fd4\u56de\u552f\u4e00\u503c<\/strong>\u3002<\/li>\n<\/ul>\n\n\n\n
      \n\n\n\n
      3. UNION ALL<\/code>\uff08\u4e0d\u53bb\u91cd\uff09<\/strong><\/h2>\n\n\n\n
      \u5982\u679c\u4f60\u5e0c\u671b\u4fdd\u7559\u91cd\u590d\u6570\u636e<\/strong>\uff0c\u53ef\u4ee5\u4f7f\u7528 UNION ALL<\/code>\uff1a<\/p>\n\n\n\n
      SELECT name FROM users1\nUNION ALL\nSELECT name FROM users2;<\/code><\/pre>\n\n\n\n
      \u7ed3\u679c<\/strong><\/p>\n\n\n\n
      name\n-------\nAlice\nBob\nBob\nCharlie<\/code><\/pre>\n\n\n\n
        \n
      • UNION ALL<\/code> \u4e0d\u4f1a\u53bb\u91cd<\/strong>\uff0c\u56e0\u6b64 Bob<\/code> \u51fa\u73b0\u4e86\u4e24\u6b21\u3002<\/li>\n<\/ul>\n\n\n\n
        \n\n\n\n
        4. ORDER BY<\/code> \u4e0e UNION<\/code><\/strong><\/h2>\n\n\n\n
        \u5982\u679c\u9700\u8981\u6392\u5e8f\uff0c\u5fc5\u987b\u653e\u5728\u6700\u540e<\/strong>\uff1a<\/p>\n\n\n\n
        SELECT name FROM users1\nUNION\nSELECT name FROM users2\nORDER BY name DESC;<\/code><\/pre>\n\n\n\n
        \u7ed3\u679c<\/strong><\/p>\n\n\n\n
        name\n-------\nCharlie\nBob\nAlice<\/code><\/pre>\n\n\n\n
        \n\n\n\n
        5. UNION<\/code> \u7ed3\u5408 WHERE<\/code><\/strong><\/h2>\n\n\n\n
        \u53ef\u4ee5\u5728\u6bcf\u4e2a SELECT<\/code> \u8bed\u53e5\u4e2d\u4f7f\u7528 WHERE<\/code> \u8fc7\u6ee4\u6570\u636e\uff1a<\/p>\n\n\n\n
        SELECT name FROM users1 WHERE id < 2\nUNION\nSELECT name FROM users2 WHERE id > 2;<\/code><\/pre>\n\n\n\n
          \n
        • users1<\/code> \u4ec5\u8fd4\u56de id < 2<\/code> \u7684\u6570\u636e\u3002<\/li>\n\n\n\n
        • users2<\/code> \u4ec5\u8fd4\u56de id > 2<\/code> \u7684\u6570\u636e\u3002<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n
          6. UNION<\/code> \u7ed3\u5408 DISTINCT<\/code><\/strong><\/h2>\n\n\n\n
          UNION<\/code> \u9ed8\u8ba4\u53bb\u91cd\uff0c\u4f46\u4f60\u4ecd\u7136\u53ef\u4ee5\u4f7f\u7528 DISTINCT<\/code>\uff1a<\/p>\n\n\n\n
          SELECT DISTINCT name FROM users1\nUNION\nSELECT DISTINCT name FROM users2;<\/code><\/pre>\n\n\n\n
            \n
          • \u8fd9\u6837\u5373\u4f7f users1<\/code> \u6216 users2<\/code> \u5185\u90e8\u6709\u91cd\u590d\u6570\u636e\uff0c\u4ecd\u7136\u53ef\u4ee5\u4fdd\u8bc1\u53bb\u91cd\u3002<\/li>\n<\/ul>\n\n\n\n
            \n\n\n\n
            7. UNION<\/code> \u9650\u5236\u7ed3\u679c\u6570<\/strong><\/h2>\n\n\n\n
            \u53ef\u4ee5\u5728\u6700\u7ec8\u67e5\u8be2\u4e2d\u4f7f\u7528 LIMIT<\/code> \u8fdb\u884c\u5206\u9875\uff1a<\/p>\n\n\n\n
            SELECT name FROM users1\nUNION\nSELECT name FROM users2\nLIMIT 2;<\/code><\/pre>\n\n\n\n
              \n
            • \u4ec5\u8fd4\u56de\u524d 2 \u884c<\/strong>\u3002<\/li>\n<\/ul>\n\n\n\n
              \n\n\n\n
              \u603b\u7ed3<\/strong><\/h2>\n\n\n\n
              \u5173\u952e\u5b57<\/th>\u4f5c\u7528<\/th><\/tr><\/thead>
              UNION<\/code><\/td>\u53bb\u91cd<\/strong>\u5408\u5e76\u591a\u4e2a SELECT<\/code> \u7ed3\u679c<\/td><\/tr>
              UNION ALL<\/code><\/td>\u4e0d\u53bb\u91cd<\/strong>\u5408\u5e76\u591a\u4e2a SELECT<\/code> \u7ed3\u679c<\/td><\/tr>
              ORDER BY<\/code><\/td>\u53ea\u80fd\u7528\u4e8e\u6700\u7ec8\u7684 SELECT<\/code> \u7ed3\u679c<\/td><\/tr>
              LIMIT<\/code><\/td>\u9650\u5236\u8fd4\u56de\u884c\u6570<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
              \n\n\n\n
              \u66f4\u591a\u8be6\u7ec6\u5185\u5bb9\u8bf7\u5173\u6ce8\u5176\u4ed6\u76f8\u5173\u6587\u7ae0\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"
              \u5728 SQLite \u4e2d\uff0cUNION \u5b50\u53e5\u7528\u4e8e\u5408\u5e76\u591a\u4e2a SELECT \u8bed\u53e5\u7684\u7ed3\u679c\uff0c\u5e76\u8fd4\u56de\u53bb\u91cd\u540e\u7684\u7ed3\u679c\u3002\u5982\u679c\u4f60\u60f3\u5305\u542b […]<\/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-2352","post","type-post","status-publish","format-standard","hentry","category-sqlite"],"_links":{"self":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2352","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=2352"}],"version-history":[{"count":1,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2352\/revisions"}],"predecessor-version":[{"id":2353,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/posts\/2352\/revisions\/2353"}],"wp:attachment":[{"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/media?parent=2352"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/categories?post=2352"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.laixuexila.com\/index.php\/wp-json\/wp\/v2\/tags?post=2352"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}