如何正确放置GROUP BY？

Question

如何使用该查询正确分组：

$sQuery = "SELECT id,DATE(A.Inspection_datetime) AS Date, 
           A.Model, COUNT(A.Serial_number) AS Qty, 
           B.name 
         FROM inspection_report AS A 
         LEFT JOIN Employee AS B 
         ON A.NIK=B.NIK 
         GROUP BY Date, B.name".$sWhere.$sOrder.$sLimit; 

我在串联真的很新。

Answer 1

至少在大多数SQL DBMS中（MySQL在此区域中有宽松规则），您同样需要GROUP BY'id'和'A.Model'。您需要GROUP BY来在WHERE子句之后和ORDER BY子句之前。因此：

$sGroupBy = " GROUP BY id, Date, A.Model, B.Name "; 
$sQuery = "SELECT id,DATE(A.Inspection_datetime) AS Date, 
          A.Model, COUNT(A.Serial_number) AS Qty, 
          B.name 
        FROM inspection_report AS A 
        LEFT JOIN Employee AS B 
        ON A.NIK=B.NIK " . 
        $sWhere.$sGroupBy.$sOrder.$sLimit; 

请注意，你必须确保有空格分开，你串联在一起的各种条款;我在$sGroupBy（和B.NIK之后）的每一端添加了一个空格，以确保该部分正常。