将Mysql数据导出到Excel下载时如何加入/合并两个表？

Question

我维护 4 张桌子。

表1（表名：products）-> pro_id, pro_model, price

表2（表名：pro_description）-> id, pro_id, pro_name, pro_desp

表3（表名：pro_to_category）-> id, pro_id, cat_id

表4（表名：类别）-> cat_id, cat_desp

现在我想下载字段，当我将 mysql 数据导出到 excel 时 下载、pro_id、pro_name、pro_desp、价格、pro_model、类别 （注：category需要cat_desp，不需要cat_id） 感谢提前。帮我解决。 :(

    <?php
/*******EDIT LINES 3-8*******/
$DB_Server = "localhost"; //MySQL Server    
$DB_Username = "username"; //MySQL Username     
$DB_Password = "password";             //MySQL Password     
$DB_DBName = "databasename";         //MySQL Database Name  
$DB_TBLName = "tablename"; //MySQL Table Name   
$filename = "excelfilename";         //File Name
/*******YOU DO NOT NEED TO EDIT ANYTHING BELOW THIS LINE*******/    
//create MySQL connection   
$sql = "Select * from $DB_TBLName";
$Connect = @mysql_connect($DB_Server, $DB_Username, $DB_Password) or die("Couldn't connect to MySQL:<br>" . mysql_error() . "<br>" . mysql_errno());
//select database   
$Db = @mysql_select_db($DB_DBName, $Connect) or die("Couldn't select database:<br>" . mysql_error(). "<br>" . mysql_errno());   
//execute query 
$result = @mysql_query($sql,$Connect) or die("Couldn't execute query:<br>" . mysql_error(). "<br>" . mysql_errno());    
$file_ending = "xls";
//header info for browser
header("Content-Type: application/xls");    
header("Content-Disposition: attachment; filename=$filename.xls");  
header("Pragma: no-cache"); 
header("Expires: 0");
/*******Start of Formatting for Excel*******/   
//define separator (defines columns in excel & tabs in word)
$sep = "\t"; //tabbed character
//start of printing column names as names of MySQL fields
for ($i = 0; $i < mysql_num_fields($result); $i++) {
echo mysql_field_name($result,$i) . "\t";
}
print("\n");    
//end of printing column names  
//start while loop to get data
    while($row = mysql_fetch_row($result))
    {
        $schema_insert = "";
        for($j=0; $j<mysql_num_fields($result);$j++)
        {
            if(!isset($row[$j]))
                $schema_insert .= "NULL".$sep;
            elseif ($row[$j] != "")
                $schema_insert .= "$row[$j]".$sep;
            else
                $schema_insert .= "".$sep;
        }
        $schema_insert = str_replace($sep."$", "", $schema_insert);
        $schema_insert = preg_replace("/\r\n|\n\r|\n|\r/", " ", $schema_insert);
        $schema_insert .= "\t";
        print(trim($schema_insert));
        print "\n";
    }   
?>

Answer 1

尝试按照以下方式进行查询：

SELECT
    t1.pro_id,
    t2.pro_name,
    t2.pro_desp,
    t1.price,
    t1.pro_model,
    t4.cat_desp
FROM products t1
INNER JOIN pro_description t2
    ON t1.pro_id = t2.pro_id
INNER JOIN pro_to_category t3
    ON t1.pro_id = t3.pro_id
INNER JOIN category t4
    ON t3.cat_id = t4.cat_id