Question

我有多个表（相同的列结构），我希望在两个日期范围之间有计数行。现在它给了我每张桌子的所有记录。每个表有大约700K记录，这使得搜索速度也很慢。我没有得到正确的查询。以下查询是我到目前为止的。

$monday = '2018-01-15';
$tuesday = '2018-01-16';

SELECT count(datetime) FROM uptime_m1 WHERE datetime 
BETWEEN '$monday' and'$tuesday' and status = 'idle' 
UNION ALL 
SELECT (datetime) FROM uptime_m2 WHERE datetime 
BETWEEN '$monday' and'$tuesday' and status = 'idle';

PHP代码：

if ($result = $mysqli->query("
SELECT count(datetime) FROM uptime_m1 WHERE datetime 
   BETWEEN '$monday' and'$tuesday' and status = 'idle' 
UNION ALL 
SELECT (datetime) FROM uptime_m2 WHERE datetime 
   BETWEEN '$monday' and'$tuesday' and status = 'idle';
")) {
   $row_cnt = $result->num_rows;
   $count_m1_idle_monday = $row_cnt;
   $result->close();
}

Answer 1

您可以使用子请求来计算每个表并对结果求和。

select
  (select count(*) from uptime_m1
   where datetime between '$monday' and '$tuesday' and status = 'idle')
+ (select count(*) from uptime_m2
   where datetime between '$monday' and '$tuesday' and status = 'idle')
as nbrows;

使用BIG DATA从两个日期之间的多个表中选择SELECT

1 个答案: