将多个SQL查询组合成单个查询

Question

我有以下三个查询，我需要将它们合并为一个。 有谁知道该怎么做？

$myTasks = "";
$query = "SELECT taskID_PK " .
            "FROM tasks t " . 
            "LEFT JOIN task_assignee ta ON ta.taskID_FK = t.taskID_PK ".
            "LEFT JOIN task_attachments a ON a.taskID_FK = t.taskID_PK ".
            "LEFT JOIN employee e ON e.employeeID_PK = t.assignByID_FK ".
            " WHERE TRUE AND isArchive != 1 AND taskStatus = 1 AND ta.clientID_FK  = {$G_CLIENID} AND categoryID_FK !=0  group by taskID_PK ";

$RawData = db::select($query);
$myTasks= count($RawData);

$closeTasks = "";
$query = "SELECT taskID_PK,taskTitle,taskDescn,categoryID_FK,priority,date_format(createDate, '%d/%m/%Y') as createDate,ticketID_FK,
            date_format(dueDate, '%d/%m/%Y') as dueDate ,assignByID_FK,createTime,  taskStatus,closedDate,employeeName ,attachmentID_PK " .
            "FROM tasks t " . 
            "LEFT JOIN task_assignee ta ON ta.taskID_FK = t.taskID_PK ".
            "LEFT JOIN task_attachments a ON a.taskID_FK = t.taskID_PK ".
            "LEFT JOIN employee e ON e.employeeID_PK = t.assignByID_FK ".
            " WHERE TRUE AND isArchive != 1 AND (taskStatus != 1 ){$taskCreateClause} AND categoryID_FK !=0  group by taskID_PK ";
$RawData = db::select($query);
$closeTasks = count($RawData);

$workLoad ="";
$query = "SELECT taskID_PK,taskTitle,taskDescn,categoryID_FK,priority,date_format(createDate, '%m/%d/%Y') as createDate,ticketID_FK,
            date_format(dueDate, '%m/%d/%Y') as dueDate ,assignByID_FK,createTime,  taskStatus,closedDate,employeeName ,clientID_FK " .
            "FROM task_assignee ta " . 
            "LEFT JOIN tasks t ON ta.taskID_FK = t.taskID_PK ".
            "LEFT JOIN employee e ON e.employeeID_PK = ta.clientID_FK ".
            " WHERE TRUE AND taskStatus = 1  ";
$RawData = db::select($query);
$workLoad = count($RawData);

Answer 1

好吧，现在我明白了这个问题，这样的事情怎么样：

select a.taskID_PK,
     (Select count(*)) .
        "FROM tasks t " . 
        "LEFT JOIN task_assignee ta ON ta.taskID_FK = t.taskID_PK ".
        "LEFT JOIN task_attachments a ON a.taskID_FK = t.taskID_PK ".
        "LEFT JOIN employee e ON e.employeeID_PK = t.assignByID_FK ".
        " WHERE TRUE AND isArchive != 1 AND taskStatus = 1 AND ta.clientID_FK  =    {$G_CLIENID} AND categoryID_FK !=0  
         and task_ID_PK = a.taskID_PK) as Count1,
         group by taskID_PK 

....
from tasks

选择主ID，然后3条独立的select语句返回一个计数，并在开头与ID结合在一起。

Answer 2

SELECT
       (SELECT(COUNT(DISTINCT t.taskID_PK))
                FROM tasks t
                LEFT JOIN task_assignee ta ON ta.taskID_FK = t.taskID_PK
                LEFT JOIN task_attachments a ON a.taskID_FK = t.taskID_PK
                LEFT JOIN employee e ON e.employeeID_PK = t.assignByID_FK
                 WHERE TRUE AND isArchive != 1 AND taskStatus = 1 AND categoryID_FK !=0)as activetasks,
        (SELECT(COUNT(DISTINCT t.taskID_PK))
                FROM tasks t
                LEFT JOIN task_assignee ta ON ta.taskID_FK = t.taskID_PK
        LEFT JOIN employee e ON e.employeeID_PK = t.assignByID_FK
                 WHERE TRUE AND isArchive != 1 AND taskStatus = 1 AND ta.clientID_FK=1 AND categoryID_FK !=0)as mytasks,
       (SELECT(COUNT(DISTINCT t.taskID_PK))
                FROM tasks t
                LEFT JOIN task_assignee ta ON ta.taskID_FK = t.taskID_PK
        LEFT JOIN employee e ON e.employeeID_PK = t.assignByID_FK
                WHERE TRUE AND isArchive != 1 AND taskStatus != 1 AND categoryID_FK !=0)as cloastasks,
        (SELECT(COUNT(t.taskID_PK))
        FROM task_assignee ta
                LEFT JOIN tasks t ON ta.taskID_FK = t.taskID_PK
                LEFT JOIN employee e ON e.employeeID_PK = ta.clientID_FK
                 WHERE TRUE AND taskStatus = 1)as workload,
        (SELECT(COUNT(DISTINCT t.taskID_PK))
                FROM tasks t
                LEFT JOIN task_assignee ta ON ta.taskID_FK = t.taskID_PK
                LEFT JOIN task_attachments a ON a.taskID_FK = t.taskID_PK
                LEFT JOIN employee e ON e.employeeID_PK = t.assignByID_FK
                 WHERE TRUE AND isArchive = 1 AND categoryID_FK !=0)as archivetasks.

我合并了查询，我想知道是否有更好的方法可以合并这些查询以提高效率？