大约有 40,000 项符合查询结果（耗时：0.0485秒） [XML]
Illegal mix of collations (utf8_unicode_ci,IMPLICIT) and (utf8_general_ci,IMPLICIT) for operation '=
...CIT) and (utf8_unicode_ci,IMPLICIT) for operation '='
$this->db->select("users.username as matric_no, CONCAT(users.surname,
' ',
users.first_name, ' ', users.last_name) as fullname")
->join('users', 'users.username=classroom_students.matric_no', 'left')
...
Warning the user/local/mysql/data directory is not owned by the mysql user
I can't start the mysql service in Snow Leopard, and in the panel prefs appears the message,
2 Answers
...
Linux iptables防火墙开放mysql、apache的端口 - 操作系统(内核) - 清泛网 ...
Linux iptables防火墙开放mysql、apache的端口vi etc sysconfig iptables 修改配置，添加两条tcp端口允许的记录：[root@iZ23rlmiwviZ ~] cat etc sysconfig iptables sample configuration for iptables service vi /etc/sysconfig/iptables 修改配置，添加两条tcp端口允许...
When should I use cross apply over inner join?
...APPLY works better on things that have no simple JOIN condition.
This one selects 3 last records from t2 for each record from t1:
SELECT t1.*, t2o.*
FROM t1
CROSS APPLY
(
SELECT TOP 3 *
FROM t2
WHERE t2.t1_id = t1.id
ORDER BY
t2.ran...
How do you connect to multiple MySQL databases on a single webpage?
...d);
$dbh2 = mysql_connect($hostname, $username, $password, true);
mysql_select_db('database1', $dbh1);
mysql_select_db('database2', $dbh2);
Then to query database 1 pass the first link identifier:
mysql_query('select * from tablename', $dbh1);
and for database 2 pass the second:
mysql_query...
Best way to select random rows PostgreSQL
I want a random selection of rows in PostgreSQL, I tried this:
12 Answers
12
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Select first row in each GROUP BY group?
As the title suggests, I'd like to select the first row of each set of rows grouped with a GROUP BY .
17 Answers
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Mysql command not found in OS X 10.7
I cant get my mysql to start on os x 10.7. It is located in /usr/local/mysql/bin/mysql
14 Answers
...
What makes a SQL statement sargable?
...non-sargable is to include a field inside a function in the where clause:
SELECT ... FROM ...
WHERE Year(myDate) = 2008
The SQL optimizer can't use an index on myDate, even if one exists. It will literally have to evaluate this function for every row of the table. Much better to use:
WHERE myDat...
Accessing inactive union member and undefined behavior?
I was under the impression that accessing a union member other than the last one set is UB, but I can't seem to find a solid reference (other than answers claiming it's UB but without any support from the standard).
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