Sql coalesce() 无法正常工作的问题

Question

我有一个查询，但我无法将 columb name 最后一行的名称更改为 'TOTAL'。结果给了我最后一行上方的行的相同名称。这是我的查询：

SELECT COALESCE(ticket_types.name,'TOTAL') AS name, 
COUNT(1) AS quantity 
FROM tr_logs 
LEFT JOIN tickets ON tr_logs.value = tickets.id 
LEFT JOIN ticket_types ON tickets.ticket_type_id = ticket_types.id 
LEFT JOIN transactions ON tr_logs.transaction_id = transactions.id 
LEFT JOIN tr_fields_data AS tfd_shipping ON tfd_shipping.transaction_id = transactions.id 
WHERE type = 'ADDITEM' 
AND transactions.event_id = '46' 
AND DATE(tr_logs.created_date) 
BETWEEN '2017-03-26' AND '2017-05-24' 
AND tfd_shipping.data IN ('0','570','571','771') 
AND name IS NOT NULL
GROUP BY ticket_types.id WITH ROLLUP

结果如下所示：

name      quantity
premium   56
outlaw    6
outlaw    62

汇总的最后一行名称不为空....我需要它是总计而不是非法的

谢谢

Answer 1

您根本没有将名称更改为 TOTAL：您已将列的名称更改为 name，并告诉它用 TOTAL.

如果你想把ticket_types.name的名字改成total，你只需要

SELECT ticket_types.name AS total ...

（但将 name 重命名为 total 会很奇怪，因此您可能需要稍微澄清一下您的要求。）

Answer 2

这可能与您观察到的问题有关，也可能无关，但是 WHERE 和 GROUP BY 子句将所有外连接转换为内连接。您应该将查询简化为：

SELECT COALESCE(tt.name, 'TOTAL') AS name, COUNT(1) AS quantity 
FROM tr_logs l JOIN
     tickets
     ON l.value = t.id JOIN
     ticket_types tt
     ON t.ticket_type_id = tt.id JOIN
     transactions tr
     ON l.transaction_id = tr.id JOIN
     tr_fields_data fd
     ON fd.transaction_id = tr.id 
WHERE type = 'ADDITEM' AND
      tr.event_id = '46' AND
      DATE(l.created_date) BETWEEN '2017-03-26' AND '2017-05-24' AND 
      fd.data IN ('0', '570', '571', '771') AND
      tt.name IS NOT NULL
GROUP BY tt.id WITH ROLLUP

Answer 3

感谢 Gordon Linoff，我解决了我的问题。

最后一行的名称永远不会为空，因为我 GROUP BY 具有不同的属性。

这是解决方案。

SELECT COALESCE(tckn,'TOTAL') AS name, quantity FROM
(SELECT tt.name AS tckn, COUNT(1) AS quantity 
FROM tr_logs AS l
LEFT JOIN tickets AS t ON l.value = t.id 
LEFT JOIN ticket_types AS tt ON t.ticket_type_id = tt.id 
LEFT JOIN transactions AS tr ON l.transaction_id = tr.id 
LEFT JOIN tr_fields_data AS tfd ON tfd.transaction_id = tr.id 
WHERE type = 'ADDITEM' 
AND tr.event_id = '46' 
AND DATE(l.created_date) 
BETWEEN '2017-03-26' AND '2017-05-24' 
AND tfd.data IN ('0','570','571','771')
GROUP BY tckn WITH ROLLUP) as sum;

Sql coalesce() 无法正常工作的问题

Sql trouble with coalesce() not working propely

mysql

sql

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