php - 在同一个句子中计算数据

Question

我有桌子：

==========================================================
|id | before | after | freq | id_sentence | document_id  |
==========================================================
| 1 |    a   |   b   | 1    |     0       |      1       |
| 2 |    c   |   d   | 1    |     1       |      1       |
| 3 |    e   |   f   | 1    |     1       |      1       |
| 4 |    g   |   h   | 2    |     0       |      2       |
==========================================================

我想获得数据的数量取决于id_sentence，freq所以结果必须是 1 2 1 这是代码：

$query = mysql_query("SELECT freq FROM tb where document_id='$doc_id' ");
    while ($row = mysql_fetch_array($query)) {
        $stem_freq = $row['freq'];
        $total = $total+$stem_freq;

但结果仍然是错误的。请帮帮我..谢谢:)

Answer 1

如果我理解您的问题，您正在尝试计算freq每个不同id_sentence的特定的总和document_id。

尝试以下 SQL：

SELECT id_sentence, SUM(freq) as freq FROM tb WHERE document_id = 1 GROUP BY(id_sentence)

结果将是具有id_sentence相应总和的数据行freq。事后无需手动总结。

请参阅此 SQL 小提琴：http ://sqlfiddle.com/#!2/691ed/8

Answer 2

我认为你可以做类似的事情

SELECT count(*) AS count FROM tb GROUP BY(id_sentence,freq)

做你想要的计数。你甚至可以做类似的事情

SELECT count(*) AS count, id_sentence, freq FROM tb GROUP BY(id_sentence,freq)

知道计数是针对哪个 id_sentence,freq 组合。