\u5982\u679c\u4ee5\u4e0b\u8f93\u51fa\u6253\u5370\u51fa\u6765\uff0c\u8bf4\u660e\u7b2c\u4e00\u4e2a\u8868\u5df2\u7ecf\u88ab\u521b\u5efa\uff1a<\/p>\n
\u8f93\u51fa<\/div>\n
\u8fd9\u662f\u6587\u7ae0\u300a\u5982\u4f55\u5728SQL\u4e2d\u4f7f\u7528\u8054\u5408\u300b\u7684\u7b2c2\u90e8\u5206\uff08\u51717\u90e8\u5206\uff09\u3002<\/p>\n
<\/code><\/pre>\nQuery OK, 0 rows affected (0.00 sec)<\/p>\n
<\/code><\/pre>\n\u7b2c\u4e8c\u4e2a\u8868\u5c06\u547d\u540d\u4e3abook_leases<\/code>\uff08\u4e66\u7c4d\u79df\u501f\uff09\uff0c\u7528\u4e8e\u5b58\u50a8\u6709\u5173\u501f\u9605\u4e66\u7c4d\u7684\u4fe1\u606f\u3002\u5b83\u7684\u7ed3\u6784\u4e0e\u524d\u4e00\u4e2a\u8868\u7c7b\u4f3c\uff0c\u4f46\u79df\u501f\u4fe1\u606f\u901a\u8fc7\u4e24\u4e2a\u4e0d\u540c\u7684\u65e5\u671f\u8fdb\u884c\u63cf\u8ff0\uff1a\u79df\u501f\u5f00\u59cb\u65e5\u671f\u548c\u79df\u501f\u7ed3\u675f\u65e5\u671f\u3002\u4e3a\u4e86\u8868\u793a\u8fd9\u4e00\u70b9\uff0cbook_leases<\/code>\u8868\u5c06\u5305\u542b\u4e94\u5217\uff1a<\/p>\n\n- lease_id<\/strong>: \u6b64\u5217\u5b58\u50a8\u79df\u501f\u6807\u8bc6\u7b26\uff0c\u6570\u636e\u7c7b\u578b\u4e3a
int<\/code>\u3002\u6b64\u5217\u5c06\u6210\u4e3a\u8868\u7684\u4e3b\u952e\uff0c\u6bcf\u4e2a\u503c\u90fd\u662f\u5176\u5bf9\u5e94\u884c\u7684\u552f\u4e00\u6807\u8bc6\u7b26\u3002<\/li>\n- customer_name<\/strong>: \u6b64\u5217\u5b58\u50a8\u5ba2\u6237\u59d3\u540d\uff0c\u6570\u636e\u7c7b\u578b\u4e3a
varchar<\/code>\uff0c\u6700\u5927\u957f\u5ea6\u4e3a30\u4e2a\u5b57\u7b26\u3002<\/li>\n- book_title<\/strong>: \u6b64\u5217\u5b58\u50a8\u501f\u9605\u4e66\u7c4d\u7684\u6807\u9898\uff0c\u6570\u636e\u7c7b\u578b\u4e3a
varchar<\/code>\uff0c\u6700\u5927\u957f\u5ea6\u4e3a200\u4e2a\u5b57\u7b26\u3002<\/li>\n- date_from<\/strong>: \u6b64\u5217\u4f7f\u7528
date<\/code>\u6570\u636e\u7c7b\u578b\uff0c\u5b58\u50a8\u79df\u501f\u7684\u5f00\u59cb\u65e5\u671f\u3002<\/li>\n- date_to<\/strong>: \u6b64\u5217\u4f7f\u7528
date<\/code>\u6570\u636e\u7c7b\u578b\uff0c\u5b58\u50a8\u79df\u501f\u7684\u7ed3\u675f\u65e5\u671f\u3002<\/li>\n<\/ul>\n\u4f7f\u7528\u4ee5\u4e0b\u547d\u4ee4\u521b\u5efa\u7b2c\u4e8c\u4e2a\u8868\uff1a<\/p>\n
<\/code><\/pre>\n\n- CREATE TABLE book_leases (<\/li>\n
- lease_id INT,<\/li>\n
- customer_name VARCHAR(30),<\/li>\n
- book_title VARCHAR(40),<\/li>\n
- date_from DATE,<\/li>\n
- date_to DATE,<\/li>\n
- PRIMARY KEY (lease_id)<\/li>\n
- );<\/li>\n<\/ol>\n
<\/code><\/pre>\n <\/p>\n
<\/code><\/pre>\n\u4ee5\u4e0b\u8f93\u51fa\u786e\u8ba4\u4e86\u7b2c\u4e8c\u5f20\u8868\u7684\u521b\u5efa\u3002<\/p>\n
<\/code><\/pre>\n\u8f93\u51fa<\/div>\n
\u8fd9\u662f\u6587\u7ae0\u300a\u5982\u4f55\u5728SQL\u4e2d\u4f7f\u7528\u8054\u5408\u300b\u7684\u7b2c3\u90e8\u5206\uff08\u51717\u90e8\u5206\uff09\u3002<\/p>\n
Query OK, 0 rows affected (0.00 sec)<\/code><\/pre>\n\u4e4b\u540e\uff0c\u8fd0\u884c\u4ee5\u4e0bINSERT INTO<\/code>\u64cd\u4f5c\uff0c\u4e3a\u8d2d\u4e70\u8868\u52a0\u8f7d\u4e00\u4e9b\u793a\u4f8b\u6570\u636e\u3002<\/p>\n\r\n\r\n \t- INSERT INTO book_purchases<\/li>\r\n \t
- VALUES<\/li>\r\n \t
- (1, 'sammy', 'The Picture of Dorian Gray', '2022-10-01'),<\/li>\r\n \t
- (2, 'sammy', 'Pride and Prejudice', '2022-10-04'),<\/li>\r\n \t
- (3, 'sammy', 'The Time Machine', '2022-09-23'),<\/li>\r\n \t
- (4, 'bill', 'Frankenstein', '2022-07-23'),<\/li>\r\n \t
- (5, 'bill', 'The Adventures of Huckleberry Finn', '2022-10-01'),<\/li>\r\n \t
- (6, 'walt', 'The Picture of Dorian Gray', '2022-04-15'),<\/li>\r\n \t
- (7, 'walt', 'Frankenstein', '2022-10-13'),<\/li>\r\n \t
- (8, 'walt', 'Pride and Prejudice', '2022-10-19');<\/li>\r\n<\/ol>\r\n<\/code><\/pre>\n
\u63d2\u5165\u64cd\u4f5c\u5c06\u628a\u5177\u6709\u6307\u5b9a\u503c\u76848\u6761\u8d2d\u4e70\u8bb0\u5f55\u6dfb\u52a0\u5230book_purchases<\/code>\u8868\u4e2d\u3002\u4e0b\u9762\u7684\u8f93\u51fa\u8868\u660e\u5df2\u6210\u529f\u6dfb\u52a0\u4e86\u5168\u90e8\u516b\u884c\u3002<\/p>\n<\/code><\/pre>\n\u8f93\u51fa<\/div>\n
\u8fd9\u662f\u6587\u7ae0\u300a\u5982\u4f55\u5728SQL\u4e2d\u4f7f\u7528\u8054\u5408\u300b\u7684\u7b2c4\u90e8\u5206\uff08\u51717\u90e8\u5206\uff09\u3002<\/p>\n
<\/code><\/pre>\nQuery OK, 8 rows affected (0.00 sec)
Records: 8 Duplicates: 0 Warnings: 0<\/p>\n
<\/code><\/pre>\n\u7136\u540e\u5c06\u4e00\u4e9b\u6837\u672c\u6570\u636e\u63d2\u5165\u5230book_leases<\/code>\u8868\u4e2d\u3002<\/p>\n<\/code><\/pre>\n\n- INSERT INTO book_leases<\/li>\n
- VALUES<\/li>\n
- (1, ‘sammy’, ‘Frankenstein’, ‘2022-09-14’, ‘2022-11-14’),<\/li>\n
- (2, ‘sammy’, ‘Pride and Prejudice’, ‘2022-10-01’, ‘2022-12-31’),<\/li>\n
- (3, ‘sammy’, ‘The Adventures of Huckleberry Finn’, ‘2022-10-01’, ‘2022-12-01’),<\/li>\n
- (4, ‘bill’, ‘The Picture of Dorian Gray’, ‘2022-09-03’, ‘2022-09-18’),<\/li>\n
- (5, ‘bill’, ‘Crime and Punishment’, ‘2022-09-27’, ‘2022-12-05’),<\/li>\n
- (6, ‘kim’, ‘The Picture of Dorian Gray’, ‘2022-10-01’, ‘2022-11-15’),<\/li>\n
- (7, ‘kim’, ‘Pride and Prejudice’, ‘2022-09-08’, ‘2022-11-17’),<\/li>\n
- (8, ‘kim’, ‘The Time Machine’, ‘2022-09-04’, ‘2022-10-23’);<\/li>\n<\/ol>\n
<\/code><\/pre>\n <\/p>\n
<\/code><\/pre>\n\u4f60\u5c06\u6536\u5230\u4ee5\u4e0b\u8f93\u51fa\uff0c\u786e\u8ba4\u6837\u672c\u6570\u636e\u5df2\u88ab\u6dfb\u52a0\u3002<\/p>\n
<\/code><\/pre>\n\u8f93\u51fa<\/p>\n
<\/code><\/pre>\nQuery OK, 8 rows affected (0.00 sec)
Records: 8 Duplicates: 0 Warnings: 0<\/p>\n
<\/code><\/pre>\n<\/div>\n\u79df\u7ea6\u548c\u8d2d\u4e70\u4e0e\u76f8\u4f3c\u7684\u987e\u5ba2\u548c\u56fe\u4e66\u6807\u9898\u6709\u5173\uff0c\u8fd9\u5c06\u6709\u52a9\u4e8e\u6f14\u793aUNION<\/code>\u8fd0\u7b97\u7b26\u7684\u884c\u4e3a\u3002<\/p>\n\u6709\u4e86\u8fd9\u4e9b\uff0c\u4f60\u5c31\u53ef\u4ee5\u7ee7\u7eed\u9605\u8bfb\u672c\u6307\u5357\uff0c\u5e76\u5f00\u59cb\u5728SQL\u4e2d\u4f7f\u7528UNION<\/code>\u64cd\u4f5c\u3002<\/p>\n\u7406\u89e3SQL\u4e2dUNION<\/code>\u8fd0\u7b97\u7b26\u7684\u8bed\u6cd5<\/h2>\n\u5728SQL\u4e2d\uff0cUNION<\/code>\u8fd0\u7b97\u7b26\u6307\u793a\u6570\u636e\u5e93\u5c06\u901a\u8fc7\u5355\u72ec\u7684SELECT<\/code>\u67e5\u8be2\u68c0\u7d22\u5230\u7684\u4e24\u4e2a\u72ec\u7acb\u7ed3\u679c\u96c6\u5408\u5e76\u4e3a\u4e00\u4e2a\u7ed3\u679c\u96c6\uff0c\u5176\u4e2d\u5305\u542b\u6765\u81ea\u4e24\u4e2a\u67e5\u8be2\u8fd4\u56de\u7684\u884c\u3002<\/p>\n\n
\u6ce8\u610f\uff1a\u6570\u636e\u5e93\u4e0d\u9650\u5236\u4e0eUNION<\/code>\u4e00\u8d77\u4f7f\u7528\u7684SELECT<\/code>\u67e5\u8be2\u7684\u590d\u6742\u6027\u3002\u6570\u636e\u68c0\u7d22\u67e5\u8be2\u53ef\u4ee5\u5305\u62ecJOIN<\/code>\u8bed\u53e5\u3001\u805a\u5408\u51fd\u6570\u6216\u5b50\u67e5\u8be2\u3002\u901a\u5e38\uff0cUNION<\/code>\u7528\u4e8e\u5408\u5e76\u6765\u81ea\u590d\u6742\u8bed\u53e5\u7684\u7ed3\u679c\u3002\u4e3a\u4e86\u6559\u80b2\u76ee\u7684\uff0c\u672c\u6307\u5357\u4e2d\u7684\u793a\u4f8b\u5c06\u4f7f\u7528\u7b80\u5355\u7684SELECT<\/code>\u67e5\u8be2\uff0c\u4ee5\u4fbf\u91cd\u70b9\u5173\u6ce8UNION<\/code>\u8fd0\u7b97\u7b26\u7684\u884c\u4e3a\u3002<\/p>\n<\/div>\n\u8fd9\u662f\u6587\u7ae0\u300a\u5982\u4f55\u5728SQL\u4e2d\u4f7f\u7528\u8054\u5408\u300b\u7684\u7b2c5\u90e8\u5206\uff08\u51717\u90e8\u5206\uff09\u3002<\/p>\n
\u4e0b\u9762\u7684\u4f8b\u5b50\u5c55\u793a\u4e86\u4e00\u4e2a\u5305\u542bUNION<\/code>\u8fd0\u7b97\u7b26\u7684SQL\u8bed\u53e5\u7684\u901a\u7528\u8bed\u6cd5\u3002<\/p>\n\r\n \t- SELECT column1, column2 FROM table1<\/li>\r\n \t
- UNION<\/mark><\/li>\r\n \t
- SELECT column1, column2 FROM table2;<\/li>\r\n<\/ol><\/code><\/pre>\n
\u8fd9\u4e2aSQL\u7247\u6bb5\u9996\u5148\u4ecetable1<\/code>\u8fd4\u56de\u4e24\u5217\uff0c\u63a5\u7740\u662fUNION<\/code>\u8fd0\u7b97\u7b26\u548c\u7b2c\u4e8c\u4e2aSELECT<\/code>\u8bed\u53e5\u3002\u7b2c\u4e8c\u4e2aSELECT<\/code>\u67e5\u8be2\u4e5f\u8fd4\u56de\u4e24\u5217\uff0c\u4f46\u5b83\u4eec\u6765\u81eatable2<\/code>\u3002UNION<\/code>\u5173\u952e\u5b57\u544a\u8bc9\u6570\u636e\u5e93\u5206\u522b\u6267\u884c\u524d\u9762\u548c\u540e\u9762\u7684\u67e5\u8be2\uff0c\u7136\u540e\u5c06\u5b83\u4eec\u7684\u7ed3\u679c\u96c6\u5408\u5e76\u3002\u6574\u4e2a\u4ee3\u7801\u7247\u6bb5\uff0c\u5305\u62ec\u4e24\u4e2aSELECT<\/code>\u67e5\u8be2\u548c\u5b83\u4eec\u4e4b\u95f4\u7684UNION<\/code>\u5173\u952e\u5b57\uff0c\u662f\u4e00\u4e2a\u5355\u72ec\u7684SQL\u8bed\u53e5\u3002\u56e0\u6b64\uff0c\u7b2c\u4e00\u4e2aSELECT<\/code>\u67e5\u8be2\u4e0d\u4ee5\u5206\u53f7\u7ed3\u675f\uff0c\u5206\u53f7\u53ea\u51fa\u73b0\u5728\u6574\u4e2a\u8bed\u53e5\u7684\u672b\u5c3e\u3002<\/p>\n\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u5047\u8bbe\u60a8\u60f3\u5217\u51fa\u6240\u6709\u8d2d\u4e70\u6216\u79df\u8d41\u8fc7\u4e00\u672c\u4e66\u7684\u5ba2\u6237\u3002\u8d2d\u4e70\u8bb0\u5f55\u5b58\u50a8\u5728book_purchases<\/code>\u8868\u4e2d\uff0c\u800c\u79df\u8d41\u8bb0\u5f55\u5b58\u50a8\u5728book_leases<\/code>\u8868\u4e2d\u3002\u60a8\u53ef\u4ee5\u6267\u884c\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n\r\n \t- SELECT customer_name FROM book_purchases<\/li>\r\n \t
- UNION<\/mark><\/li>\r\n \t
- SELECT customer_name FROM book_leases;<\/li>\r\n<\/ol><\/code><\/pre>\n
\u8fd9\u662f\u8fd9\u4e2a\u67e5\u8be2\u7684\u7ed3\u679c\u96c6\u3002<\/p>\n
\u8f93\u51fa<\/div>\n
+---------------+\r\n| customer_name |\r\n+---------------+\r\n| sammy |\r\n| bill |\r\n| walt |\r\n| kim |\r\n+---------------+\r\n4 rows in set (0.000 sec)<\/code><\/pre>\n\u8fd9\u4e2a\u7ed3\u679c\u8868\u660e\uff0cSammy\u3001Bill\u3001Walt\u548cKim\u90fd\u5728\u67d0\u4e2a\u65f6\u95f4\u8d2d\u4e70\u6216\u79df\u501f\u8fc7\u4e66\u7c4d\u3002\u8981\u7406\u89e3\u8fd9\u4e2a\u7ed3\u679c\u96c6\u662f\u5982\u4f55\u4ea7\u751f\u7684\uff0c\u60a8\u53ef\u4ee5\u5c1d\u8bd5\u5206\u522b\u6267\u884c\u4e24\u4e2aSELECT<\/code>\u8bed\u53e5\uff1a\u4e00\u4e2a\u7528\u4e8e\u8d2d\u4e70\u8bb0\u5f55\uff0c\u4e00\u4e2a\u7528\u4e8e\u79df\u8d41\u8bb0\u5f55\u3002<\/p>\n\u8fd0\u884c\u4ee5\u4e0b\u67e5\u8be2\u4ee5\u8fd4\u56de\u8d2d\u4e70\u4e66\u7c4d\u7684\u5ba2\u6237\u3002<\/p>\n
\r\n \t- SELECT customer_name FROM book_purchases;<\/li>\r\n<\/ol><\/code><\/pre>\n
\u4e0b\u9762\u7684\u8f93\u51fa\u5c06\u6253\u5370\u5230\u5c4f\u5e55\u4e0a\uff1a<\/p>\n
\u8f93\u51fa<\/div>\n
+---------------+\r\n| customer_name |\r\n+---------------+\r\n| sammy |\r\n| sammy |\r\n| sammy |\r\n| bill |\r\n| bill |\r\n| walt |\r\n| walt |\r\n| walt |\r\n+---------------+\r\n8 rows in set (0.000 sec)<\/code><\/pre>\nSammy\u3001Bill \u548c Walt \u8d2d\u4e70\u4e86\u4e66\uff0c\u4f46\u662f Kim \u6ca1\u6709\u8d2d\u4e70\u3002<\/p>\n
\u63a5\u4e0b\u6765\uff0c\u8fd0\u884c\u67e5\u8be2\u4ee5\u8fd4\u56de\u79df\u501f\u56fe\u4e66\u7684\u5ba2\u6237\u3002<\/p>\n
\r\n \t- SELECT customer_name FROM book_leases;<\/li>\r\n<\/ol><\/code><\/pre>\n
\u4e0b\u9762\u7684\u8f93\u51fa\u5c06\u6253\u5370\u5230\u5c4f\u5e55\u4e0a\uff1a<\/p>\n
\u8f93\u51fa<\/div>\n
+---------------+\r\n| customer_name |\r\n+---------------+\r\n| sammy |\r\n| sammy |\r\n| sammy |\r\n| bill |\r\n| bill |\r\n| kim |\r\n| kim |\r\n| kim |\r\n+---------------+\r\n8 rows in set (0.000 sec)<\/code><\/pre>\n\u79df\u8d41\u8868\u4e2d\u6d89\u53ca\u7684\u4eba\u5305\u62ec Sammy\u3001Bill \u548c Kim\uff0c\u4f46 Walt \u4ece\u672a\u79df\u501f\u8fc7\u4e66\u3002\u5c06\u8fd9\u4e24\u4e2a\u7ed3\u679c\u5408\u5e76\uff0c\u60a8\u5c31\u53ef\u4ee5\u83b7\u5f97\u79df\u8d41\u548c\u8d2d\u4e70\u7684\u7efc\u5408\u6570\u636e\u3002<\/p>\n
\u4f7f\u7528UNION<\/code>\u4e0e\u5355\u72ec\u6267\u884c\u4e24\u4e2a\u67e5\u8be2\u4e4b\u95f4\u7684\u91cd\u8981\u533a\u522b\u5728\u4e8e\uff0cUNION<\/code>\u9664\u4e86\u5408\u5e76\u7ed3\u679c\u5916\uff0c\u8fd8\u4f1a\u5220\u9664\u91cd\u590d\u7684\u503c\uff1a\u6700\u7ec8\u7ed3\u679c\u4e2d\u6ca1\u6709\u91cd\u590d\u7684\u5ba2\u6237\u59d3\u540d\u3002<\/p>\n\u4e3a\u4e86\u6b63\u786e\u5730\u4f7f\u7528UNION<\/code>\u5408\u5e76\u4e24\u4e2a\u72ec\u7acb\u67e5\u8be2\u7684\u7ed3\u679c\uff0c\u8fd9\u4e24\u4e2a\u67e5\u8be2\u90fd\u5e94\u4ee5\u76f8\u540c\u7684\u683c\u5f0f\u8fd4\u56de\u7ed3\u679c\u3002\u4e00\u4e9b\u4e0d\u4e00\u81f4\u4f1a\u5bfc\u81f4\u6570\u636e\u5e93\u5f15\u64ce\u62a5\u9519\uff0c\u800c\u53e6\u4e00\u4e9b\u5219\u4f1a\u7ed9\u51fa\u4e0d\u7b26\u5408\u67e5\u8be2\u610f\u56fe\u7684\u7ed3\u679c\u3002<\/p>\n\u8003\u8651\u4ee5\u4e0b\u4e24\u4e2a\u4f8b\u5b50\uff1a<\/p>\n
\u8054\u5408\u67e5\u8be2\u65f6\u5217\u4e0d\u5339\u914d<\/h3>\n
\u5c1d\u8bd5\u6267\u884c\u4e00\u4e2aUNION<\/code>\u64cd\u4f5c\uff0c\u5176\u4e2d\u5305\u542b\u4e00\u4e2a\u8fd4\u56de\u5355\u5217\u7684SELECT<\/code>\u8bed\u53e5\u548c\u53e6\u4e00\u4e2a\u8fd4\u56de\u4e24\u5217\u7684SELECT<\/code>\u8bed\u53e5\u3002<\/p>\n\r\n \t- SELECT purchase_id, customer_name<\/mark> FROM book_purchases<\/li>\r\n \t
- UNION<\/li>\r\n \t
- SELECT customer_name<\/mark> FROM book_leases;<\/li>\r\n<\/ol><\/code><\/pre>\n
\u6570\u636e\u5e93\u670d\u52a1\u5668\u5c06\u8fd4\u56de\u4e00\u4e2a\u9519\u8bef\u3002<\/p>\n
\u8f93\u51fa<\/div>\n
The used SELECT statements have a different number of columns<\/code><\/pre>\n\u4e0d\u53ef\u80fd\u5bf9\u5177\u6709\u4e0d\u540c\u5217\u6570\u7684\u7ed3\u679c\u96c6\u6267\u884c\u8054\u5408\u64cd\u4f5c\u3002<\/p>\n
\u5217\u987a\u5e8f\u4e0d\u5339\u914d\u7684UNION<\/h3>\n
\u5c1d\u8bd5\u6267\u884c\u4e00\u4e2aUNION<\/code>\u64cd\u4f5c\uff0c\u8be5\u64cd\u4f5c\u4f1a\u5c06\u8fd4\u56de\u76f8\u540c\u503c\u4f46\u987a\u5e8f\u4e0d\u540c\u7684\u4e24\u4e2aSELECT<\/code>\u8bed\u53e5\u8fdb\u884c\u5408\u5e76\u3002<\/p>\n\r\n \t- SELECT customer_name, book_title<\/mark> FROM book_purchases<\/li>\r\n \t
- UNION<\/li>\r\n \t
- SELECT book_title, customer_name<\/mark> FROM book_leases;<\/li>\r\n<\/ol><\/code><\/pre>\n
\u6570\u636e\u5e93\u670d\u52a1\u5668\u4e0d\u4f1a\u8fd4\u56de\u9519\u8bef\uff0c\u4f46\u7ed3\u679c\u96c6\u5c06\u4e0d\u6b63\u786e\u3002<\/p>\n
\u8f93\u51fa<\/div>\n
\u8fd9\u662f\u6587\u7ae0\u300a\u5982\u4f55\u5728SQL\u4e2d\u4f7f\u7528\u8054\u5408\u300b\u7684\u7b2c6\u90e8\u5206\uff08\u51717\u90e8\u5206\uff09\u3002<\/p>\n
+------------------------------------+------------------------------------+\r\n| customer_name | book_title |\r\n+------------------------------------+------------------------------------+\r\n| sammy | The Picture of Dorian Gray |\r\n| sammy | Pride and Prejudice |\r\n| sammy | The Time Machine |\r\n| bill | Frankenstein |\r\n| bill | The Adventures of Huckleberry Finn |\r\n| walt | The Picture of Dorian Gray |\r\n| walt | Frankenstein |\r\n| walt | Pride and Prejudice |\r\n| Frankenstein | sammy |\r\n| Pride and Prejudice | sammy |\r\n| The Adventures of Huckleberry Finn | sammy |\r\n| The Picture of Dorian Gray | bill |\r\n| Crime and Punishment | bill |\r\n| The Picture of Dorian Gray | kim |\r\n| Pride and Prejudice | kim |\r\n| The Time Machine | kim |\r\n+------------------------------------+------------------------------------+\r\n16 rows in set (0.000 sec)<\/code><\/pre>\n\u5728\u8fd9\u4e2a\u4f8b\u5b50\u4e2d\uff0cUNION<\/code> \u64cd\u4f5c\u5c06\u7b2c\u4e00\u4e2a\u67e5\u8be2\u7684\u7b2c\u4e00\u5217\u4e0e\u7b2c\u4e8c\u4e2a\u67e5\u8be2\u7684\u7b2c\u4e00\u5217\u5408\u5e76\uff0c\u5e76\u5c06\u7b2c\u4e8c\u5217\u505a\u76f8\u540c\u7684\u64cd\u4f5c\uff0c\u4ece\u800c\u5c06\u987e\u5ba2\u540d\u79f0\u548c\u4e66\u7c4d\u6807\u9898\u6df7\u5408\u5728\u4e00\u8d77\u3002<\/p>\n\u5728SQL\u4e2d\u4f7f\u7528WHERE\u5b50\u53e5\u548cORDER BY\u5b50\u53e5\u4e0eUNION\u7ed3\u5408<\/h2>\n
\u5728\u524d\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u4f60\u5408\u5e76\u4e86\u4ee3\u8868\u4e24\u4e2a\u5bf9\u5e94\u8868\u4e2d\u6240\u6709\u884c\u7684\u7ed3\u679c\u96c6\u3002\u901a\u5e38\uff0c\u5728\u5408\u5e76\u7ed3\u679c\u4e4b\u524d\uff0c\u4f60\u9700\u8981\u7b5b\u9009\u884c\u3002\u4f7f\u7528UNION<\/code>\u8fd0\u7b97\u7b26\u5408\u5e76\u7684SELECT<\/code>\u8bed\u53e5\u53ef\u4ee5\u4f7f\u7528WHERE<\/code>\u5b50\u53e5\u6765\u5b9e\u73b0\u7b5b\u9009\u3002<\/p>\n\u5047\u8bbe\u4f60\u60f3\u901a\u8fc7\u4f60\u7684\u4e66\u5e97\u8d2d\u4e70\u6216\u79df\u8d41\u7684\u65b9\u5f0f\u77e5\u9053Sammy\u8bfb\u4e86\u54ea\u4e9b\u4e66\u3002\u8fd0\u884c\u4ee5\u4e0b\u67e5\u8be2\uff1a<\/p>\n
\r\n \t- SELECT book_title FROM book_purchases<\/li>\r\n \t
- WHERE customer_name = 'Sammy'<\/mark><\/li>\r\n \t