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It could be much more efficient to find the lone duplicate and delete just it, without doing all the joining. My current query that fills the temp table is more complicated.
Hi Erni, not exactly sure what you need to do. Hi recently I was asked by an interviewer and the question is as follows, I am having duplicate names irrespective of the original name. If the tables had an ID and the ID was all the same, but the name was different you could do the following:.
Friday, March 02, 2012 - 1: For example my name is Dorababu some of them inserted as Dhorababu or dorebabu like this. I would like to delete the remaining except Dorababu from the table how can I do this. In this example, our results look like this:. Tuesday, April 10, 2012 - 7: This will become the innermost query in your self-join. I write about topics such as technology, entrepreneurship, and fitness, and I tweet at xaprb. This post have been posted for more than two year but it helped me alot.
Related 2779. So as you can see with SQL Server 2005 and later there are two options to allow you to delete duplicate identical rows of data in your tables. Suppose you need to remove all sales persons that live in the US from the esqlSalesPerson table.
If we try to select the record for Bob Smith will all of the available values such as the following query:. Back To Top. So to make it easier and more efficient I thought I would post process the temp table by removing all those customers. And because I assumed a relatively small, non-mission-critical task, I suggested you can make a temporary table to aid in deleting the duplicate rows.
For instance, you have a hundred million rows and only one duplicate row. This will also only work on versions of MySQL where subqueries are implemented.
Specifically, I assumed a beginner programmer who designs a table, connects some program to it, and then discovers a bunch of duplicate data because of incorrect table design. Assuming you really do need a table to hold that information at all, and can't use a view or a CTE for whatever you're doing... By setting it to 1 we can just delete one of these rows in the table.
Wednesday, October 31, 2018 - 3: