大约有 40,000 项符合查询结果（耗时：0.0179秒） [XML]
Multiple select statements in Single query
...
SELECT (
SELECT COUNT(*)
FROM user_table
) AS tot_user,
(
SELECT COUNT(*)
FROM cat_table
) AS tot_cat,
(
SELECT COUNT(*)
FROM course_table
) AS tot_course
...
What is the difference between “INNER JOIN” and “OUTER JOIN”?
...he intersection of the two tables, i.e. the two rows they have in common.
select * from a INNER JOIN b on a.a = b.b;
select a.*, b.* from a,b where a.a = b.b;
a | b
--+--
3 | 3
4 | 4
Left outer join
A left outer join will give all rows in A, plus any common rows in B.
select * from a LEFT OUT...
MySQL - SELECT WHERE field IN (subquery) - Extremely slow why?
...
Rewrite the query into this
SELECT st1.*, st2.relevant_field FROM sometable st1
INNER JOIN sometable st2 ON (st1.relevant_field = st2.relevant_field)
GROUP BY st1.id /* list a unique sometable field here*/
HAVING COUNT(*) > 1
I think st2.relevant_...
Rename MySQL database [duplicate]
...be found using a
query on information_schema.TABLES table.
mysql> select TABLE_NAME from information_schema.tables where
table_schema='<old_schema_name>' and TABLE_TYPE='BASE TABLE';
3) Dump the views in an out file. Views can be found using a query on
the same information_...
Access denied for user 'test'@'localhost' (using password: YES) except root user
...' IDENTIFIED BY 'password';
This statement creates a new user and grants selected privileges to it.
I.E.:
GRANT INSERT, SELECT, DELETE, UPDATE ON database.* TO 'user'@'localhost' IDENTIFIED BY 'password';
Take a look at the docs to see all privileges detailed
EDIT: you can look for more info w...
How to get a list of user accounts using the command line in MySQL?
...
Use this query:
SELECT User FROM mysql.user;
Which will output a table like this:
+-------+
| User |
+-------+
| root |
+-------+
| user2 |
+-------+
As Matthew Scharley points out in the comments on this answer, you can group by the ...
Install MySQL on Ubuntu without a password prompt
...
sudo debconf-set-selections <<< 'mysql-server mysql-server/root_password password your_password'
sudo debconf-set-selections <<< 'mysql-server mysql-server/root_password_again password your_password'
sudo apt-get -y install ...
ERROR 1130 (HY000): Host '' is not allowed to connect to this MySQL server [duplicate]
...d with localhost access (which is recommended).
You can check this with:
SELECT host FROM mysql.user WHERE User = 'root';
If you only see results with localhost and 127.0.0.1, you cannot connect from an external source. If you see other IP addresses, but not the one you're connecting from - that...
LR性能测试结果样例分析 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...是否达到了预期的性能指标，其中又有哪些性能隐患，该如何解决。
图1- 1性能测试结果分析流程图
结果摘要
LoadRunner进行场景测试结果收集后，首先显示的该结果的一个摘要信息，如图1- 2所示。概要中列出了场景执行...
Inserting multiple rows in mysql
...
it's also possible to use INSERT INTO Table SELECT 1, '14/05/2012', 3 UNION SELECT 2, '05/14/2012', 3. of course, this will only be better of the inserted values are coming from different tables.
– Zohar Peled
Jun 1 '15 at 9:18
...