Which query in MySQL can delete duplicate ID records from data?
MySQL can remove duplicates record mainly in three ways.
- Delete Duplicate Record Using Delete Join. We can use the DELETE JOIN statement in MySQL that allows us to remove duplicate records quickly.
- Delete Duplicate Record Using the ROW_NUMBER() Function.
- DELETE Duplicate Rows Using Intermediate Table.
How can we find duplicate rows in a table without primary key?
- You can use a cte add a row_number() with partition and then delete where row_num > 1 I will work on example. – Matt.
- @Matt Can you give an example? – Don Rhummy.
- All there for you, your test data, select before and after the delete.
- Possible duplicate of How to delete duplicate rows in sql server?
How to remove duplicate records in MySQL, in a table without IDs?
There is no any field combination which identifies the record uniqually. I see at least 2 different solutions. First solution: move unique records to a copy of table and replace original table. Second solution: add temporary autoincrement, delete records using it, and drop temp field.
How to get rid of duplicates in SSIs?
Using Fuzzy Group Transformation in SSIS If you are using SSIS to upload data to your target table, you can use a Fuzzy Grouping Transformation before inserting records to the destination table to ignore duplicate records and insert only unique records.
How to remove duplicate records in SQL Server?
In this approach we pull distinct records from the target table into a temporary table, then truncate the target table and finally insert the records from the temporary table back to the target table as you can see in Script #3. Three things you need to be aware of when you are using this approach.
When to use unique identifier instead of ID field?
Sometimes a timestamp field is used instead of an ID field. If you want a unique identifier for every row, you could just add one (a serial, or a guid), and treat it like a surrogate key.