Hi All I have a MySQL table and it contains around 20,000,00 records. id(promary key and autogenerate),review(text),hash(int)) is the table structure
There is a column called "hash",which has the hash value (generated programatcally) I am pretty sure that there is duplicate records in my table.Thats y i generated a hash. Now i would like to dedupe the table using hash. This is the query i used for the said purpose Positive : table name id : auto generated id hash : hash value review : reviews delete Positive from Positive, ( select MIN(id) minIdent, hash s from Positive m group by hash having count(1) > 1 ) as derived where Positive.hash= derived.s and id > minIdent The above dedupe query is working.I checked it in a tabel which contains 10,000 records.All the duplicate hash values are removed. But my problem is while trying the same query in large table (20,000,00),it takes too long. On a test run the query runs 24 hours and not completed Is there anything which is wrong. Because I am not that much expert in DB -- ********************************** JAGANADH G http://jaganadhg.freeflux.net/blog *ILUGCBE* http://ilugcbe.techstud.org _______________________________________________ ILUGC Mailing List: http://www.ae.iitm.ac.in/mailman/listinfo/ilugc