Java: How to Load CSV file into Database. Import CSV Java
While processing I make the assumption of using UTF-8 encoding, but if the user gives me file which is special character (non-english letters) my processing barfs out with exception. Is using batch update is suitable or is there another way to insert the data, 1 record per times,update it until it finish? I hope you understand what I want to say.Sorry for the trouble
How to: Use MySQL fast LOAD DATA for UPDATEs - Software Projects Inc.
Display Modes Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Rate This Thread You have already rated this thread Enjoyed this post? Subscribe Now to receive new posts via Email as soon as they come out. Yes, using a persistent MySQL connection does improve performance of multiple INSERTs a bit but it's still a far cry from the performance of LOAD DATA and persistent connections are a bad idea
select * from mytable union select * from mytable, thsi query returns the exact records, and i guess we can use this data to build a new table or replacing the previous one. I need to get rid of the duplications, meaning that when names are shown more than once for a given month and year, I only want one of the duplicated intervention records to show up
We extensively use GROUP BY and we all know problem with GROUP BY (We should have all selected column from select clause in group by clause, other wise we cannot use group by). The problem is: the system by mistake inserted duplicate data in R2-R5 (R1 is PK assuem autonumber) and in one of these duplicates R6 and R7 are also filled
Newest Questions - Database Administrators Stack Exchange
replication mysql-5.5 mysql-event asked 6 hours ago IGGt 382111 1 vote 1answer 18 views Laravel MySQL relation difficulties I have a "users" table: And an organisations table ("orgs"): And this is the pivot table: I have some relations: On the "users" table, I have a function called "orgs()" which is a ... mysql performance asked 3 hours ago George 1011 1 vote 2answers 38 views Get the nth distinct column value ordered by another column I want to get the row with the nth distinct value in a column, as ordered by another column
Mysql Remove Duplicate Data or Rows With DISTINCT
Reply Link kaushik December 1, 2011, 9:24 amthanx jafar..that is gr8 man..:) Reply Link Aaron April 18, 2012, 7:59 pmWorks well, but be cautioned that both the duplicates are deleted, I almost got in trouble with this. (Record 4 would be the undesired record in this case) Forcing a unique index on the email and acctid column would wipe out row 2 and 4, when we only want to get rid of row 4.In situations like this, its a good idea to write your code to check for an existing record already containing those two pieces of information before you insert a new record
How can I set up iTunes on each of the computers to only import links to the songs on the network drive to its library, and also remove the dupes?? Pellet LOL how wrong you are Pralz, iTunes is created exclusively by Apple and Quicktime was created exclusively by Apple from the start. once the files are unhidden, just drag the highlighted folders over ur itunes library and itunes will automatically put the songs in and give them all the correct info about the song name, artist, etc
http://javarevisited.blogspot.com/2012/12/how-to-remove-duplicates-elements-from-ArrayList-Java.htmlIf you have a ArrayList which can contain duplicates but you need to operate with only unique elements with same order, then you need to remove those duplicates. but don't worry there is another way of removing duplicates from ArrayList without losing order of elements, for that instead of HashSet we need to use LinkedHashSet, Which guarantees insertion order
First, familiarize yourself with the basic techniques I explained for finding the duplicate rows, especially the section on finding the data you need to delete them. Xaprb How to delete duplicate rows with SQL Wed, Oct 11, 2006 in Databases The comments on my article how to find duplicate rows with SQL made me realize I was simplifying things too much
sql - How to delete duplicate rows from an Oracle Database? - Stack Overflow
To select features that have duplicates would be: select count(*) from TABLE GROUP by FID Unfortunately I can't figure out how to go from that to a SQL delete statement that will delete extraneous rows leaving only one of each. Simply put, I'd like an SQL statement to delete one version of a row while keeping the other; I don't mind which version is deleted as they're identical
sql - How can I remove duplicate rows? - Stack Overflow
Automatically SQL SERVER ignore (there is also an option about what to do if there will be a duplicate value: ignore, interrupt or sth) duplicate values. Factors which might favour the hash aggregate approach would be No useful index on the partitioning columns relatively fewer groups with relatively more duplicates in each group In extreme versions of this second case (if there are very few groups with many duplicates in each) one could also consider simply inserting the rows to keep into a new table then TRUNCATE-ing the original and copying them back to minimise logging compared to deleting a very high proportion of the rows
http://javarevisited.blogspot.com/2012/12/how-to-find-duplicate-records-in-table-mysql-query-example.htmlYou can see in first query that it listed Ruby as duplicate record even though both Ruby have different phone number because we only performed group by on name. Can you please write something about DB performance tuning as well as its being repetitvely asked to me and am unable to convince a great deal as I havent really worked on such scenarios December 17, 2012 at 8:07 AM Anonymous said..
No comments:
Post a Comment