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Oracle 分组后取每组第一条数据 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...据Oracle 分组后取每组第一条数据的SQL如下，亲测有效：SELECT * FROM (SELECT ROW_NUMBER() OVER(PARTITION BY T field1, T Oracle 分组后取每组第一条数据的SQL如下，亲测有效：
SELECT *
FROM (SELECT ROW_NUMBER() OVER(PARTITION BY T.field1, T.field2 ORDER...
nvarchar和varchar相互转换、联合查询 - ORACLE - 清泛IT论坛，有思想、有深度
...atype is NVARCHAR2.
（A表字段c_xxx:varchar，B表c_xxx:nvarchar）
select translate(c_xxx USING NCHAR_CS) from A
union all
select c_xxx from B
或者
select c_xxx from A
union all
select translate(c_xxx USING CHAR_CS) from B
注意：translate函数括号中没有逗号。
1、...
How to see log files in MySQL?
...print the value of error log, run this command in the terminal:
mysql -e "SELECT @@GLOBAL.log_error"
To read content of the error log file in real time, run:
sudo tail -f $(mysql -Nse "SELECT @@GLOBAL.log_error")
Note: Hit Control-C when finish
When general log is enabled, try:
sudo tail -f ...
Delimiters in MySQL
...TABLE tablea (
col1 INT,
col2 INT
);
INSERT INTO tablea
SELECT * FROM table1;
CREATE TABLE tableb (
col1 INT,
col2 INT
);
INSERT INTO tableb
SELECT * FROM table2;
/* whole procedure ends with the custom delimiter */
END$$
/* Finally, reset the delimiter to...
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')
...
How to delete a property from Google Analytics
...
You have to select the Property first and then under Profile click on Profile Settings. At the bottom of that page there is a "delete this profile" link:
This was really annoying, and I spent a good chuck of time trying to find th...
How do I get the collection of Model State Errors in ASP.NET MVC?
...he ModelState, use this Linq:
var modelStateErrors = this.ModelState.Keys.SelectMany(key => this.ModelState[key].Errors);
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How do I specify different layouts for portrait and landscape orientations?
...mes depending on orientation and resolution, the device will automatically select the right one for its screen settings
More info here:
http://developer.android.com/guide/practices/screens_support.html
under "Resource directory qualifiers for screen size and density"
...
Convert MySql DateTime stamp into JavaScript's Date format
...d.
A MySQL DATETIME column can be converted to a unix timestamp through:
SELECT unix_timestamp(my_datetime_column) as stamp ...
We can make a new JavaScript Date object by using the constructor that requires milliseconds since the epoch. The unix_timestamp function returns seconds since the epoc...
iOS - Dismiss keyboard when touching outside of UITextField
... the view, and then call resign first responder on the UITextField on it's selector.
The code:
In viewDidLoad
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(dismissKeyboard)];
[self.view addGestureRecognizer:tap];
In dismissKeyboard:
-(void)...