$Customer.send(“今日”).count
SELECT COUNT(*) FROM "customers" WHERE (`customers`.created_at >
'2014-02-07 05:00:00.000000')
ActiveRecord::StatementInvalid: PG::SyntaxError: ERROR: syntax error
at or near "."
LINE 1: ...LECT COUNT(*) FROM "customers"
我对EF有些问题。因此,我的mysql表中有1000000条记录。我需要有限制的查询。例如,我使用跳过50000进行查询
var listRoutes = (from c in context.Routes
where c.Alias != ""
orderby c.Alias ascending
select c).Skip(50000).Take(500).ToList();
而listRoutes有500条记录。如果
我已经从我的SQL表中分解了我想要的信息的单个SQL查询,但是我对如何将所有语句组合到一个变量上感到困惑。在PHP中使用这个变量来显示我的数据。
下面是我想要运行的SQL查询。
SELECT * FROM weather ORDER BY stamp DESC LIMIT 1
SELECT SUM(rainfall) FROM weather WHERE stamp >= CURDATE()) AS total_rainfall
SELECT MAX(maxwind) FROM weather WHERE stamp >= CURDATE()) AS max_windspee
我正试着从这张桌子上得到所有的应用程序名
SELECT id, name FROM app_names
使用这些数据获取这些结果
SELECT count(*) FROM users_dailyrecords WHERE day='x' appName='THE ID FROM THE SELECT ABOVE'
有了这个查询的结果,我想把它插入到
INSERT INTO app_stats (appID, day, totalUsers) VALUES ('appID', 'x', 'RESULT FROM count(
假设我有这样一个MySQL查询:
SELECT id,
something,
CASE colour
WHEN 1 THEN 'not ripe'
WHEN 2 THEN 'ripe'
ELSE 'rotten'
END AS 'ripeness'
FROM fruit
WHERE fruit_type = 'apple'
如果我将CASE封装在括号中,因为我发现它更易读:
SELECT id,
我有下一个mysql查询
SELECT DISTINCT * FROM dom_small WHERE count>=0 AND dom NOT IN
(SELECT dom FROM dom_small WHERE was_blocked=1)
ORDER BY count DESC LIMIT 30 OFFSET 4702020
当我越来越多地增加偏移量时,子查询运行得越来越长。
当偏移量为0时mysql查询加载0秒但当4702020 mysql查询加载1分19秒49秒时
如何解决这个问题?
问题:
我有一个返回大型结果集的查询。它太大了,不能带入PHP。我得到一个致命的内存最大错误,不能增加内存限制。
我需要多次迭代数组,但是mysqli_data_seek不能处理无缓冲的查询。
//I have a buffered result set
$bresult = $mysql->query("SELECT * FROM Small_Table");
//And a very large unbuffered result set
$uresult = $mysqli->query("SELECT * FROM Big_Table",
我正在学习数据库索引。
这是一张桌子的索引。这张桌子有330 K条记录。
mysql> show index from employee;
+----------+------------+-------------+--------------+---------------+-----------+-------------+----------+--------+------+------------+---------+---------------+---------+------------+
| Table | Non_unique | Key_name | S
我正在用Mysql数据库开发一个CodeIgniter应用程序,它将包含大量数据。
我的查询如下
SELECT id, code, name, category, purchase_price, retail_price, expiry_date, color_code, sub_category FROM products ORDER BY id DESC
在这方面,如何进行最快的SELECT查询?
如何度量查询执行时间?
我正在尝试运行一个如下所示的查询:
$DB->query("INSERT INTO table (
SELECT s.value1, s.value2, s.value3, t.value1, u.value1, u.value2, u.value3, u.value4
FROM aTable AS s
LEFT JOIN aTable2 AS u ON u.uID = s.uid
WHERE u.spent < ". $needed ."
GROUP BY s.uid, s.fid )
ON DUPLICATE KEY UPDA
我有以下代码,执行一个非常简单的MySQL查询:
$netnestquery = 'SELECT (`nested`+1) AS `nest` FROM `ipspace6` WHERE `id`<='.$adaddr.' AND `subnet`<='.$postmask.' AND `type`="net" AND `addr` NOT IN(SELECT `id` FROM `ipspace6` WHERE `addr`<'.$adaddr.' AND `type`="broadcast