MySQL PHP 如果来自 Table 的关键词短语在句子中不存在 Table 显示结果

Question

我有两个 tables：句子，否定。

我想 select 列 Sentences.sentence 不包含 Negatives.negphrase 中的任何记录。

Sentences 有 200k 条记录，Negatives 有 50k 条记录。

Sentences.sentence Sample Data
=============================

 - university lab on campus
 - laboratory designs
 - lab coats
 - math lab
 - methane production
 - meth lab

Negatives.negphrase Sample Data
======================================

 - coats
 - math lab
 - meth

Desired Result Set
==================

 - university lab on campus
 - laboratory designs
 - methane production

我尝试使用我的另一个问题的结果，但数据库超时：

SELECT Sentences.sentence
FROM Sentences, Negatives
GROUP BY Sentences.sentence
HAVING (((Max(InStr(" " & sentence & " "," " & negphrase & " ")))=0));

我的答案

所以我会给 Richard b/c 正确的答案，他的解决方案确实适用于较小的记录集，但不适用于较大的记录集。这是我用来将所有否定关键字放入数组中的 PHP 代码，然后使用 UPDATE 子句遍历该数组以在句子 table 中标记新列 'negmatch'。我将在另一个 WHERE 子句中使用它 select Sentences.sentence WHERE negmatch <> 1.

我只需要运行对所有否定短语使用此代码一次，然后当我添加其他关键字时，我使用相同的代码但没有循环来再次搜索句子（代码未在下面显示）。代码需要 6.5 分钟来循环遍历 2800 个 UPDATE 子句，因此初始加载相当长，但是一旦完成就不必再次完成。

<?php
$mysqli = new mysqli("localhost", "myuser", "myuserpassword", "database");

/* check connection */
if ($mysqli->connect_errno) {
    printf("Connect failed: %s\n", $mysqli->connect_error);
    exit();
}

if ($result = $mysqli->query("SELECT negphrase FROM negatives")) {  
    $row_cnt = $result->num_rows;
    printf("Negative keywords have %d rows.\n", $row_cnt); //print count of rows

    while($row = $result->fetch_assoc()){ //loop through all results by row
        foreach( $row  AS $value ) {
        $negative[] = $value;
    }
}


    /* free result set */
    $result->close();

    $data = array_values($negative); // get only values
    $data = array_filter($data);
    $datacount = 1;
    foreach($data as $val) { //loop through array to build MySQL WHERE clause


            $updatequery = "UPDATE Sentences SET negmatch=1 WHERE sentence REGEXP '[[:<:]]" . trim($val) . "[[:>:]]'";
            echo $updatequery  . "<br />";

            mysqli_query($mysqli,$updatequery) or die (mysqli_error($mysqli));
            echo $datacount . " " . trim($val) ."<br />";
            $datacount++;

        }

}
$mysqli->close();


    unset($result, $row, $mysqli,$value,$negative,$data,$val,$updatequery,$datacount,$row_cnt);

?>

Answer 1

SELECT t1.sentence FROM Sentences as t1
inner join Negatives as t2 on t1.sentence != t2.negphrase

确保两列都正确索引

Answer 2

使用否定左连接，这将 return 只有来自 Senteces table 的行根据规则

与否定 table 不匹配

select * from Sentences s 
left join Negatives n 
on (concat(" ",s.sentence," ") like concat("% ",n.negphrase," %"))
where n.negphrase is null

根据以下数据进行测试

CREATE TABLE IF NOT EXISTS `Negatives` (
  `negphrase` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `Negatives` (`negphrase`) VALUES
('coats'),
('math lab'),
('meth');

CREATE TABLE IF NOT EXISTS `Sentences` (
  `sentence` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

INSERT INTO `Sentences` (`sentence`) VALUES
('university lab on campus'),
('laboratory designs'),
('lab coats'),
('math lab'),
('methane production'),
('meth lab'),
('testing sentence');

MySQL PHP 如果来自 Table 的关键词短语在句子中不存在 Table 显示结果

MySQL PHP If Keyword Phrase From Table Does Not Exist In Sentence Table Show Results

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