Question

我正在尝试编写一个查询，根据今天的日期计算行的SUMS和总条目。我的数据库中的日期字段是03/14/2012 2:03:19格式。该查询忽略日期并返回数据库中所有条目的SUM。这是我的疑问：

$string = "
  SELECT SUM(totalcollected)
  FROM accounting
  WHERE agent = '$agentid'
    AND DATE(date) = DATE(NOW())
    AND amount1type = 'Cash'
     OR amount2type = 'Cash'
";

有什么建议吗？

Answer 1

看看MySQL Operator Precedence chart。您会注意到AND与OR相比具有更高的优先级，因此您的查询会变为：

SELECT SUM(totalcollected)
FROM accounting
WHERE
(
    agent = '$agentid' AND
    DATE(DATE) = DATE(NOW()) AND
    amount1type = 'Cash' 
)
OR
(
    amount2type = 'Cash'
)

请注意，当（i）代理人= $代理人（ii）amount1type = cash时，会考虑日期;但是无论日期如何，都将返回具有amount2type = cash的行。你应该添加括号来告诉MySQL究竟应该如何处理where子句：

SELECT SUM(totalcollected)
FROM accounting
WHERE
agent = '$agentid' AND
DATE(DATE) = DATE(NOW()) AND
(
    amount1type = 'Cash' OR amount2type = 'Cash'
)

Answer 2

我的猜测是你在where条款中遗漏了一些问题......

最终条件or amount2type = 'cash'允许其他所有条件都为假。您应该将其更改为与amount1type：

的检查分组

SELECT SUM(amount1), SUM(amount2), SUM(monpay), SUM(totalcollected) 
FROM accounting 
WHERE
    agent = '$agentid' 
    AND DATE(date) = DATE(NOW()) 
    AND (amount1type = 'Cash' OR amount2type = 'Cash')

Answer 3

问题是AND在 OR之前解析了，但你可以完全避免OR这个很酷的伎俩：

SELECT SUM(totalcollected) FROM accounting WHERE agent = '$agentid' AND DATE(date) = DATE(NOW()) AND 'Cash' IN (amount1type, amount2type)

Answer 4

您需要使用括号来向数据库表示您实际尝试执行的操作。更好的格式化将使其更清晰

SELECT SUM(totalcollected)
FROM accounting
WHERE agent = '$agentid'
    AND  DATE(date) = DATE(NOW())
    AND amount1type = 'Cash'
    OR amount2type = 'Cash'

与

SELECT SUM(totalcollected)
FROM accounting
WHERE agent = '$agentid'
    AND  DATE(date) = DATE(NOW())
    AND (amount1type = 'Cash' OR amount2type = 'Cash')

MySQL查询失败

4 个答案: