大约有 41,000 项符合查询结果（耗时：0.0372秒） [XML]
What is SELF JOIN and when would you use it? [duplicate]
...et information for both people in one row, you could self join like this:
select e1.EmployeeID,
e1.FirstName,
e1.LastName,
e1.SupervisorID,
e2.FirstName as SupervisorFirstName,
e2.LastName as SupervisorLastName
from Employee e1
left outer join Employee e2 on e1.SupervisorID ...
Is it safe to use -1 to set all bits to true?
... on datasets of N bits by breaking it down into chunks of sizeof(unsigned)*CHAR_BIT bits each.
– MSalters
May 4 '09 at 7:22
2
...
How to remove a Gitlab project?
...
Go to the project page
Select "Settings"
Select the "General" section (you must be in the repository you want to delete to delete it)
If you have enough rights, then at the bottom of the page will be a button for "Advanced settings" (i.e. project s...
Naming of ID columns in database tables
...!)and forget to change the alias in the join condition.
So you now have
select t1.field1, t2.field2, t3.field3
from table1 t1
join table2 t2 on t1.id = t2.table1id
join table3 t3 on t1.id = t3.table2id
when you meant
select t1.field1, t2.field2, t3.field3
from table1 t1
join table2 t2 on t1...
Extracting specific columns in numpy array
...
I assume you wanted columns 1 and 9?
To select multiple columns at once, use
X = data[:, [1, 9]]
To select one at a time, use
x, y = data[:, 1], data[:, 9]
With names:
data[:, ['Column Name1','Column Name2']]
You can get the names from data.dtype.names…
...
ORACLE 常用日期函数 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...的日期。如果给出一负数，返回值日期之前几个月日期。select add_months(to_date(&...ADD_MONTHS函数在输入日期上加上指定的几个月返回一个新的日期。如果给出一负数，返回值日期之前几个月日期。
select add_months(to_date('20150201','yyyymmd...
Uniq by object attribute in Ruby
What's the most elegant way to select out objects in an array that are unique with respect to one or more attributes?
14 An...
iPhone app signing: A valid signing identity matching this profile could not be found in your keycha
...
Open Xcode. Click WINDOW > ORGANIZER. Then click the Devices tab and select "Provisioning Profiles" on the left.
That should bring up your provisioning profiles. Highlight one by one (if more than 1), right click and delete profile. Yes, just do it! Delete them all! (I kept making a new one a...
How do I export a project in the Android studio?
...
Now "android:debuggalbe=false" is not needed and you can select build type when exporting a signed APK.
– echo
Sep 4 '14 at 10:28
4
...
SQL Server: Query fast, but slow from procedure
...:
CREATE PROCEDURE GetOrderForCustomers(@CustID varchar(20))
AS
BEGIN
SELECT *
FROM orders
WHERE customerid = @CustID
END
Fast way:
CREATE PROCEDURE GetOrderForCustomersWithoutPS(@CustID varchar(20))
AS
BEGIN
DECLARE @LocCustID varchar(20)
SET @LocCustID = @CustID
SELEC...