Question

如何从mysql中选择数据以便显示？

我有3张桌子

1表：h_test

 ____________________
|  id  |    pro_id   |
|  1   |    111111   |
|  2   |    222222   |
|  3   |    333333   |
|  4   |    444444   |
|__5___|____555555___|

2表：c_test

 __________________________________
|  id  |    pro_id   |   country   |
|  1   |    111111   |     usa     |
|  2   |    111111   |     uk      |
|  3   |    222222   |     usa     |
|  4   |    222222   |    china    |
|  5   |    333333   |     usa     |
|  6   |    333333   |     uk      |
|  7   |    444444   |    japan    |
|  8   |    444444   |     usa     |
|  9   |    555555   |     uk      |
|__10__|____555555___|_____japan___|

3表：i_test

 __________________________________
|  id  |    pro_id   |   number    |
|  1   |    111111   |     10      |
|  2   |    111111   |     20      |
|  3   |    222222   |     1       |
|  4   |    222222   |     5       |
|  5   |    333333   |     10      |
|  6   |    333333   |     20      |
|  7   |    444444   |     20      |
|  8   |    444444   |     50      |
|  9   |    555555   |     1       |
|__10__|____555555___|_____5_______|

然后我运行此代码

$SQL = "SELECT * FROM h_test INNER JOIN c_test ON c_test.pro_id = h_test.pro_id
                             INNER JOIN i_test ON i_test.pro_id = h_test.pro_id
        WHERE h_test.pro_id != '0' AND c_test.country = 'usa' AND i_test.number > '5' GROUP BY h_test.pro_id order by i_test.number desc ";

在测试代码之后，我得到了这个数据

 _______________________________________________
|  id  |    pro_id   |   country   |   number  |
|  7   |    444444   |     usa     |     20    |
|  1   |    111111   |     usa     |     10    |
|__5___|____333333___|_____usa_____|_____10____|

但我想获得这样的数据，如何选择

 _______________________________________________
|  id  |    pro_id   |   country   |   number  |
|  7   |    444444   |     usa     |     50    |
|  1   |    111111   |     usa     |     20    |
|__5___|____333333___|_____usa_____|_____20____|

我该怎么做？

Answer 1

$SQL = "SELECT c.id, c.pro_id, b.country, max(c.number) FROM h_test a 
        INNER JOIN c_test b ON a.pro_id = b.pro_id
        INNER JOIN i_test c ON a.pro_id = c.pro_id
        WHERE a.pro_id != '0' AND b.country = 'usa' AND c.number > '5' GROUP BY a.pro_id order by c.number desc";

或

$SQL = "SELECT i_test.id, i_test.pro_id, c_test.country, max(i_test.number) FROM h_test INNER JOIN c_test ON c_test.pro_id = h_test.pro_id INNER JOIN i_test ON i_test.pro_id = h_test.pro_id
        WHERE h_test.pro_id != '0' AND c_test.country = 'usa' AND i_test.number > '5' GROUP BY h_test.pro_id order by i_test.number desc ";

Answer 2

您的查询中必须进行一些调整

$ SQL =＆＃34; SELECT * FROM h_test INNER JOIN c_test ON c_test.pro_id = h_test.pro_id INNER JOIN i_test ON i_test.pro_id = h_test.pro_id 在哪里h_test.pro_id！=＆＃39; 0＆＃39; AND c_test.country =＆＃39; usa＆＃39; AND i_test.number＆gt; ＆＃39; 5＆＃39; AND i_test.pro_id in（SELECT max（pro_id）FROM i_test GROUP BY number）＆＃34;;

如何从mysql中选择数据进行显示？

2 个答案: