使用 mysql 变量连接

Question

我的查询中的问题，尤其是在这篇文章中：

@a:= concat(@a, ',', B.call_account_id) AS paid_account_id

这是整个查询：

SELECT operator_id, paid_account_ids,  SUM( goods_count * price ) AS sales_volume, count(*) AS sales_cnt
FROM (
    SELECT B.operator_id, @a:= concat(@a, ',', B.call_account_id) AS paid_account_ids, B.call_time, A.goods_count, A.price, UNIX_TIMESTAMP( A.completion_date ) AS paid_ts
    FROM call_module_data B
    INNER JOIN ak_accounts A ON ( A.account_id = B.call_account_id AND A.goods_count >=1 )
    WHERE B.call_status IN (1,7) AND A.status_id = 5
    AND operator_id IN ( $op_ids )
    $and_str_accounts
    GROUP BY A.account_id
    HAVING call_time < (paid_ts + $time_shift)
    ) AS T
GROUP BY operator_id";

所以上面提到的表达式应该产生连接的帐户 ID 字符串（例如 3341,4355,4433...）。但是我得到了 NULL 而不是所需的字符串。 请帮忙解决。提前致谢。

Answer 1

使用GROUP_CONCAT() 函数代替字符串连接

改变

@a:= concat(@a, ',', B.call_account_id) AS paid_account_id

上面的字符串到

GROUP_CONCAT(B.call_account_id) AS paid_account_ids

最终答案：

SELECT operator_id, GROUP_CONCAT(paid_account_ids) AS paid_account_ids, 
       SUM(goods_count * price) AS sales_volume, COUNT(*) AS sales_cnt
FROM (SELECT B.operator_id, GROUP_CONCAT(B.call_account_id) AS paid_account_ids, 
             B.call_time, A.goods_count, A.price, 
             UNIX_TIMESTAMP(A.completion_date) AS paid_ts
      FROM call_module_data B
      INNER JOIN ak_accounts A ON A.account_id = B.call_account_id AND A.goods_count >=1
      WHERE B.call_status IN (1,7) AND A.status_id = 5 AND operator_id IN ($op_ids)
            $and_str_accounts
      GROUP BY A.account_id HAVING call_time < (paid_ts + $time_shift)
     ) AS T
GROUP BY operator_id;