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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...
Android add placeholder text to EditText
...
In Android Studio you can add Hint (Place holder) through GUI. First select EditText field on designer view. Then Click on Component Tree Left side of IDE (Normally it's there, but it may be there minimized) There you can see Properties of selected EditText. Find Hint field as below Image
T...
python pandas remove duplicate columns
...,False,True].
Pandas allows one to index using boolean values whereby it selects only the True values. Since we want to keep the unduplicated columns, we need the above boolean array to be flipped (ie [True, True, False] = ~[False,False,True])
Finally, df.loc[:,[True,True,False]] selects only the...
Simplest way to profile a PHP script
...connect_to_db();
prof_flag("Perform query");
// Get all the data
$select_query = "SELECT * FROM data_table";
$result = mysql_query($select_query);
prof_flag("Retrieve data");
$rows = array();
$found_data=false;
while($r = mysql_fetch_assoc($result))
{
$found_data=tru...
adding and removing classes in angularJs using ng-click
...s code actuali change class for all div, how I can apply class only to the selected clicked item
– xzegga
Apr 24 '14 at 4:44
...
Fix code indentation in Xcode
...
Before Xcode 9 (for Xcode 9 see default shortcut below)
select text
right-click
there's a "Re-indent selection" item in popup menu
In XCode 4 there is one more step:
select text
right-click
Click on "Structure"
there's a "Re-indent selection" and other options in popup men...
Mysql - How to quit/exit from stored procedure
...RE v_workflow_count INT(10);
-- checking if workflow created for package
select count(*) INTO v_workflow_count from workflow w where w.package_id =
package_id ;
this_proc:BEGIN -- this_proc block start here
IF v_workflow_count = 0 THEN
select 'no work flow ' as 'workflow_status' ;
...
Use tnsnames.ora in Oracle SQL Developer
...s shown in below image.
In the Preferences options expand Database --> select Advanced --> under "Tnsnames Directory" --> Browse the directory where tnsnames.ora present.
Then click on Ok,
as shown in below diagram.
tnsnames.ora available at Drive:\oracle\product\10x.x.x\client_x\NETWORK\A...
Compare two data.frames to find the rows in data.frame 1 that are not present in data.frame 2
...ata.frame(a = 1:3, b=letters[1:3])
require(sqldf)
a1NotIna2 <- sqldf('SELECT * FROM a1 EXCEPT SELECT * FROM a2')
And the rows which are in both data frames:
a1Ina2 <- sqldf('SELECT * FROM a1 INTERSECT SELECT * FROM a2')
The new version of dplyr has a function, anti_join, for exactly the...
Combine :after with :hover
I want to combine :after with :hover in CSS (or any other pseudo selector). I basically have a list and the item with the selected class has an arrow shape applied using :after . I want the same to be true for objects that are being hovered over but cant quite get it to work. Heres the cod...