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有and 有OR的依据几个字段生成SQL语句

WBOY
WBOYOriginal
2016-06-13 13:16:57778browse

有and 有OR的根据几个字段生成SQL语句
有如下图的数据表信息,有什么好的方法把它们组合成一条SQL?如果全是and 的或者全是or的,这方法好办,可是两个同时都有的,怎么办呢?



全是AND 或OR的话

PHP code
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        $sql = "select * from sk_cvfilter where cvid=58 and columnname!=''";
        $query = mysql_query($sql);
        $sql = '';
        while($row = mysql_fetch_assoc($query)){
            if($row['comparator']=='eq'){$comparator="=";}
            else{$comparator=$row['comparator'];}
            $sql .=$row['columnname'].$comparator."'".$row['value']."' ".$row['andor'].' ';
        }



------解决方案--------------------
SQL code
select * from sk_cvfilter where cvid=58 and columnname!='' and andor='and' or andor='or'
<br><font color="#e78608">------解决方案--------------------</font><br>你的这个记录有问题,为什么呢?<br><br>例如出现一个 (a = 1 or (b=2 and b=3)),这个时候,你是怎么记录的?<br><br>我猜是这样的<br><br>columnname   comparator   value   andor<br>a            eq           1       or<br>b            eq           2       and<br>c            eq           3      <br><br>这个时候问题出现了,假如你不知道上面的那个关系式(a = 1 or (b=2 and b=3)),<br>如果只从结构看的话,你是认为<br><br>(a = 1 or b =2 ) and b = 3<br><br>还是<br><br>  a = 1 or (b=2 and b=3)<br><br>上述问题不考虑,所有or为一个条件和其他条件and的写法<br><br><br>
PHP code

<?php $sql = "select * from sk_cvfilter where cvid=58 and columnname!=''";
$query = mysql_query($sql);
$sql = '';

// 记录上一句的是不是or
$is_last_or = false;


while($row = mysql_fetch_assoc($query)){
    if($row['comparator']=='eq'){$comparator="=";}
    else{$comparator=$row['comparator'];}
    
    
    if($is_last_or) {
        if($row['andor'] == 'and') {
            // 和下一句是and关系说明括号要结束了
            $sql .=$row['columnname'].$comparator."'".$row['value']."' ) ".$row['andor'].' ';
        } else {
            // 持续括号里的内容
            $sql .=$row['columnname'].$comparator."'".$row['value']."' ".$row['andor'].' ';
        }
    } elseif($row['andor'] == 'or') {
        // 如果有or则意味着和下一句有或的关系(因为你这里没有括号)
        $is_last_or = true;
        // 加上括号吧
        $sql .= '( ' . $row['columnname'].$comparator."'".$row['value']."' ".$row['andor'].' ';
    } else {
        $sql .=$row['columnname'].$comparator."'".$row['value']."' ".$row['andor'].' ';
    }
    
}
<br /><font color="#e78608">------解决方案--------------------</font><br>
PHP code

<?php $sql = "select * from sk_cvfilter where cvid=58 and columnname!=''";
$query = mysql_query($sql);
$sql = '';

// 记录上一句的是不是or
$is_last_or = false;


while($row = mysql_fetch_assoc($query)){
    if($row['comparator']=='eq'){$comparator="=";}
    else{$comparator=$row['comparator'];}
    
    
    if($is_last_or) {
        if($row['andor']  != 'or') {
            // 和下一句是and或者结束了关系说明括号要结束了
            $sql .=$row['columnname'].$comparator."'".$row['value']."' ) ".$row['andor'].' ';
        } else {
            // 持续括号里的内容
            $sql .=$row['columnname'].$comparator."'".$row['value']."' ".$row['andor'].' ';
        }
    } elseif($row['andor'] == 'or') {
        // 如果有or则意味着和下一句有或的关系(因为你这里没有括号)
        $is_last_or = true;
        // 加上括号吧
        $sql .= '( ' . $row['columnname'].$comparator."'".$row['value']."' ".$row['andor'].' ';
    } else {
        $sql .=$row['columnname'].$comparator."'".$row['value']."' ".$row['andor'].' ';
    }
    
} <div class="clear">
                 
              
              
        
            
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