Question

我更改了代码中的查询，因为我希望用户从下拉列表中选择特定值，而不是自由文本搜索。在这种情况下，我必须适应以下事实：如果用户未选择特定值，我仍然希望获得所有相关结果。更改后，查询将返回“无结果”。我很困惑，因为我已经多次使用过类似的查询。这是有效的原始查询：

SELECT `companies`.`name`, `companies`.`website`,`country`.`country_name`, 
        `company_sector`.`notes`, `sector`.`sector_name`, 
        FORMAT(`financials`.`revenues`,0), 
        FORMAT(`financials`.`ebitda`,0) 
FROM { oj `seta`.`company_sector` AS `company_sector` 
    RIGHT OUTER JOIN `seta`.`companies` AS `companies` ON `company_sector`.`company_id` = `companies`.`company_id` 
    LEFT OUTER JOIN `seta`.`country` AS `country` ON `country`.`country_id` = `companies`.`country_id` 
    LEFT OUTER JOIN `seta`.`financials` AS `financials` ON `financials`.`company_id` = `companies`.`company_id` 
    LEFT OUTER JOIN `seta`.`contacts` AS `contacts` ON `contacts`.`contact_id` = `companies`.`seta_id` 
    }, 
`seta`.`sector` AS `sector` 
WHERE 
      (
        (`company_sector`.`sector_id` = `sector`.`sector_id`)
      AND 
        (`companies`.`name` LIKE '%".$query_name."%')
      AND 
        (`company_sector`.`notes` LIKE '%".$query_product."%')
      AND 
        (`country`.`country_name` LIKE '%".$query_country."%')
      AND 
        (`sector`.`sector_name` LIKE '%".$query_sector."%')

这是无效的新查询。如您所见，我仅更改了最后两行。

SELECT `companies`.`name`, `companies`.`website`, `country`.`country_name`, 
        `company_sector`.`notes`, `sector`.`sector_name`, 
        FORMAT(`financials`.`revenues`,0), 
        FORMAT(`financials`.`ebitda`,0) 
FROM { oj `seta`.`company_sector` AS `company_sector` 
    RIGHT OUTER JOIN `seta`.`companies` AS `companies` ON `company_sector`.`company_id` = `companies`.`company_id` 
    LEFT OUTER JOIN `seta`.`country` AS `country` ON `country`.`country_id` = `companies`.`country_id` 
    LEFT OUTER JOIN `seta`.`financials` AS `financials` ON `financials`.`company_id` = `companies`.`company_id` 
    LEFT OUTER JOIN `seta`.`contacts` AS `contacts` ON `contacts`.`contact_id` = `companies`.`seta_id` }, `seta`.`sector` AS `sector` 
WHERE 
     ( 
      (`company_sector`.`sector_id` = `sector`.`sector_id`)
      AND 
      (`companies`.`name` LIKE '%".$query_name."%')
      AND 
      (`company_sector`.`notes` LIKE '%".$query_product."%')
      AND
       (
        (`company_sector`.`sector_id` = ".$query_sector.") 
        OR 
        (".$query_sector." IS NULL)
       )
      ) 
       ORDER BY `financials`.`revenues` ASC

可以帮忙吗？谢谢问候托马索

Answer 1

中断查询到各节，并在选择过滤器后附加过滤器值。参见下面的示例。

$query = "SELECT `companies`.`name`, `companies`.`website`, `country`.`country_name`, `company_sector`.`notes`, `sector`.`sector_name`, FORMAT(`financials`.`revenues`,0), FORMAT(`financials`.`ebitda`,0) FROM { oj `seta`.`company_sector` AS `company_sector` RIGHT OUTER JOIN `seta`.`companies` AS `companies` ON `company_sector`.`company_id` = `companies`.`company_id` LEFT OUTER JOIN `seta`.`country` AS `country` ON `country`.`country_id` = `companies`.`country_id` LEFT OUTER JOIN `seta`.`financials` AS `financials` ON `financials`.`company_id` = `companies`.`company_id` LEFT OUTER JOIN `seta`.`contacts` AS `contacts` ON `contacts`.`contact_id` = `companies`.`seta_id` }, `seta`.`sector` AS `sector` WHERE 
             ( 
              (`company_sector`.`sector_id` = `sector`.`sector_id`)
              AND 
              (`companies`.`name` LIKE '%".$query_name."%')
              AND 
              (`company_sector`.`notes` LIKE '%".$query_product."%')";

//check if filter is selected. 
if(!empty($query_sector)){
        $query .= " AND `company_sector`.`sector_id` = ".$query_sector; //append to main query.
}

$query .= " ORDER BY `financials`.`revenues` ASC";

Answer 2

您假设一个空字符串与此行匹配IS NULL：

(".$query_sector." IS NULL)

那将永远无法解决。

您的意思是：

(".$query_selector." = '')

更改简单参数将在null时中断MySql查询

2 个答案: