数据库内容只有 9100 篇文章但是同时命中了这个查询
SELECT *
FROM `ABC`
WHERE st=6 AND publish_on <= '2018-02-01'
ORDER BY rand() LIMIT 5
查询时间：1.043072 锁定时间：0.000081 已发送行数：5 已检查行数：19354
但 ：
Select count(*) from ABC;
它返回：
9100
为什么它检查 19354 行？
您好我尝试在PayPal中使用EURO创建付款但收到错误.但是当我使用美元付款时,它工作正常.
[TIMESTAMP] => 2014-09-26T10:03:06Z
[CORRELATIONID] => 4d802c104e0ae
[ACK] => Failure
[VERSION] => 64
[BUILD] => 13055236
[L_ERRORCODE0] => 10444
[L_SHORTMESSAGE0] => Transaction refused because of an invalid argument. See additional error messages for details.
[L_LONGMESSAGE0] => The transaction currency specified must be the same as previously specified.
[L_SEVERITYCODE0] => Error