Rookie question, about the array, please provide the algorithm, thank you
$arrItem = Array (
Array (' Code ' =>10000, ' name ' = ' China ', ' s ' =>1),
Array (' Code ' =>30000, ' name ' = ' France ', ' s ' =>50),
Array (' Code ' =>30000, ' name ' = ' France ', ' s ' =>100),
Array (' Code ' =>10000, ' name ' = ' China ', ' s ' =>3),
Array (' Code ' =>20000, ' name ' = ' us ', ' s ' =>2),
Array (' Code ' =>3
duplicate records appear in the table I created for testing (without indexing. Later I summarized some methods for deleting duplicate records. In Oracle, you can delete duplicate records by using the unique rowid. You can also create a temporary table... this article only mentions several simple and practical methods. I hope you can share them with us (using the table "employee" as an example ).
SQL> DESC employee
Name null? Type
-----------------------------------------------------------------
Bandwidth connection error 691 (Access denied due to invalid domain user name or password)/error 635 (unknown error) process is as follows:(1) Incorrect username and password(2) If the user account and password are correct, proceed to the next step. We recommend that you re-build the dialing software (if you do not know how to install the dialing software, refer to the user again ):? If the dialing software is normal after being reinstalled, the reason is "the dialing software is lost ";? If the
"conNtimeout ": 10000,//Integer-how long (in milliseconds) to wait for the control connection to be established. default:10000 "Pasvtimeout": 10000,//Integer-how long (in milliseconds) to wait for a PASV data connection to be E Stablished. default:10000 "KeepAlive": 10000,/
duplicate records appear in the table I created for testing (without indexing. Later I summarized some methods for deleting duplicate records. in Oracle, you can delete duplicate records by using the unique rowid. you can also create a temporary table... this article only mentions several simple and practical methods. I hope you can share them with us (using the table "employee" as an example ).
SQL> desc employee
Name Null? Type
-----------------------------------------------------------------
the copy package, the difference between the two functions is recursive replication. The efficiency is not the same: (The following program runs in Ipython)import copya = range(100000)%timeit -n 10 copy.copy(a) # 运行10次 copy.copy(a)%timeit -n 10 copy.deepcopy(a)10 loops, best of 3: 1.55 ms per loop10 loops, best of 3: 151 ms per loopThe Timeit followed by-n indicates the number of runs, and the next two lines correspond to the output of two Timeit. This shows that the latter is one order of magn
structures such as dict and list, direct value assignment uses the reference method. In some cases, the entire object needs to be copied. In this case, copy and deepcopy in the copy package can be used. The difference between the two functions is that the latter is recursively copied. Different efficiency: (the following programs run in ipython)
Import copya = range (100000) % timeit-n 10 copy. copy (a) # Run copy 10 times. copy (a) % timeit-n 10 copy. deepcopy (a) 10 loops, best of 3: 1.55 MS
EFind_in_set (B.game, replace (a.game, '-', ', '))andFind_in_set (C.channel, replace (A.channel, '-', ', '))To get this result.
ID time UID Game Channel system Screen Network1 1421812389 10000 All games WIN7 1024x768 Telecom3 1421812389 10000 All games WIN7 1024x768 Telecom1 1421812389 10000 World of Warcraft WIN7 1024x768 Telecom3 1421812389
NecklaceFrog have \ (n\) gems arranged in a cycle, whose beautifulness is \ (a_1, a_2, \dots, a_n\). She would like to remove some gems to make them into a beautiful necklace without changing their relative order.Note that a beautiful necklace can is divided into \ (3\) consecutive parts \ (X, y, z\), where
\ (x\) consists of gems with non-decreasing beautifulness,
\ (y\) is the only perfect gem. (A perfect gem is a gem whose beautifulness equals to \ (
Many people do not know how SQL statements are executed in SQL Server, fearing that their written SQL statements will be misunderstood by SQL Server. Like what:
SELECT * FROM table1 where name= ' Zhangsan ' and TID > 10000
and implementation:
SELECT * FROM table1 where TID > 10000 and name= ' Zhangsan '
Some people do not know the execution efficiency of the above two statements is the same, because if
implemented to reduce the number of reads to the base table to achieve SQL optimization. Of course, the actual situation may be more complex, use this idea to rewrite the time to pay attention to the SQL statement test validation. Attach the test script for this article Create Tableheadertable (Headeridint, Othercolumnvarchar( -)
)
Create Tabledetailtable (Headeridint, Detailidint Identity(1,1), Detailkeyvarchar( -), Detailvaluesint
)
Declare @i int = 0
while @i1000000
begin
Insert i
Tags: connection process different now reduced rollup switch decision limita lot of people don't know How SQL statements are executed in SQL Server, and they worry that the SQL statements they write are misunderstood by SQL Server. Like what:1.select * FROM table1 where name= ' Zhangsan ' and TID > 10000 and execute SELECT * FROM table1 where TID > 10000 and name= ' Z Hangsan "Some people do not know whethe
Many people do not know how SQL statements are executed in SQL Server. They are worried that the SQL statements they write will be misunderstood by SQL Server. For example:
Select * From Table1 where name = 'hangsan' and TID> 10000
And execution:
Select * From Table1 where TID> 10000 and name = 'hangsan'
Some people do not know whether the execution efficiency of the preceding two statements is the same, be
Many people do not know how SQL statements are executed in SQL Server. They are worried that the SQL statements they write will be misunderstood by SQL Server. For example:
Select * From Table1 where name = 'hangsan' and TID> 10000
And execution:
Select * From Table1 where TID> 10000 and name = 'hangsan'
Some people do not know whether the execution efficiency of the preceding two statements is th
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.