Question

I’m trying to dedup a table, where I know there are ‘close’ (but not exact) rows that need to be removed.

I have a single table, with 22 fields, and uniqueness can be established through comparing 5 of those fields. Of the remaining 17 fields, (including the unique key), there are 3 fields that cause each row to be unique, meaning the dedup proper method will not work.

I was looking at the multi table delete method outlined here: http://blog.krisgielen.be/archives/111 but I can’t make sense of the final line of code (AND M1.cd*100+M1.track > M2.cd*100+M2.track) as I am unsure what the cd*100 part achieves…

Can anyone assist me with this? I suspect I could do better exporting the whole thing to python, doing something with it, then re-importing it, but then (1)I’m stuck with knowing how to dedup the string anyway! and (2) I had to break the record into chunks to be able to import it into mysql as it was timing out after 300 seconds so it turned into a whole debarkle to get into mysql in the first place…. (I am very novice at both mysql and python)

The table is a dump of some 40 log files from some testing. The test set for each log is some 20,000 files. The repeating values are either the test conditions, the file name/parameters or the results of the tests.

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    CREATE SHOW TABLE:

    CREATE TABLE `t1` (
     `DROID_V` int(1) DEFAULT NULL,
     `Sig_V` varchar(7) DEFAULT NULL,
     `SPEED` varchar(4) DEFAULT NULL,
     `ID` varchar(7) DEFAULT NULL,
     `PARENT_ID` varchar(10) DEFAULT NULL,
     `URI` varchar(10) DEFAULT NULL,
     `FILE_PATH` varchar(68) DEFAULT NULL,
     `NAME` varchar(17) DEFAULT NULL,
     `METHOD` varchar(10) DEFAULT NULL,
     `STATUS` varchar(14) DEFAULT NULL,
     `SIZE` int(10) DEFAULT NULL,
     `TYPE` varchar(10) DEFAULT NULL,
     `EXT` varchar(4) DEFAULT NULL,
     `LAST_MODIFIED` varchar(10) DEFAULT NULL,
     `EXTENSION_MISMATCH` varchar(32) DEFAULT NULL,
     `MD5_HASH` varchar(10) DEFAULT NULL,
     `FORMAT_COUNT` varchar(10) DEFAULT NULL,
     `PUID` varchar(15) DEFAULT NULL,
     `MIME_TYPE` varchar(24) DEFAULT NULL,
     `FORMAT_NAME` varchar(10) DEFAULT NULL,
     `FORMAT_VERSION` varchar(10) DEFAULT NULL,
     `INDEX` int(11) NOT NULL AUTO_INCREMENT,
     PRIMARY KEY (`INDEX`)
    ) ENGINE=MyISAM AUTO_INCREMENT=960831 DEFAULT CHARSET=utf8

The only unique field is the PriKey, ‘index’.

Unique records can be established by looking at DROID_V,Sig_V,SPEED.NAME and PUID

Of the ¬900,000 rows, I have about 10,000 dups that are either a single duplicate of a record, or have upto 6 repetitions of the record.

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Row examples: As Is

    5;"v37";"slow";"10266";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/7";"image/tiff";"Tagged Ima";"3";"191977"
    5;"v37";"slow";"10268";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/8";"image/tiff";"Tagged Ima";"4";"191978"
    5;"v37";"slow";"10269";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/9";"image/tiff";"Tagged Ima";"5";"191979"
    5;"v37";"slow";"10270";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/10";"image/tiff";"Tagged Ima";"6";"191980"
    5;"v37";"slow";"12766";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/7";"image/tiff";"Tagged Ima";"3";"193977"
    5;"v37";"slow";"12768";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/8";"image/tiff";"Tagged Ima";"4";"193978"
    5;"v37";"slow";"12769";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/9";"image/tiff";"Tagged Ima";"5";"193979"
    5;"v37";"slow";"12770";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/10";"image/tiff";"Tagged Ima";"6";"193980"

Row Example: As It should be

    5;"v37";"slow";"10266";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/7";"image/tiff";"Tagged Ima";"3";"191977"
    5;"v37";"slow";"10268";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/8";"image/tiff";"Tagged Ima";"4";"191978"
    5;"v37";"slow";"10269";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/9";"image/tiff";"Tagged Ima";"5";"191979"
    5;"v37";"slow";"10270";;"file:";"V1-FL425817.tif";"V1-FL425817.tif";"BINARY_SIG";"MultipleIdenti";"20603284";"FILE";"tif";"2008-11-03";;;;"fmt/10";"image/tiff";"Tagged Ima";"6";"191980"

Please note, you can see from the index column at the end that I have cut out some other rows – I have only idenitified a very small set of repeating rows. Please let me know if you need any more ‘noise’ from the rest of the DB

Thanks.

Answer 1

I figured out a fix – using the count function, I was using a COUNT(*) that just returned everything in the table, by using a COUNT (distinct NAME) function I am able to weed out the dup rows that fit the dup critera (as set out by the field selection in a WHERE clause)

Example:

SELECT `PUID`,`DROID_V`,`SIG_V`,`SPEED`, COUNT(distinct NAME) as Hit FROM sourcelist, main_small WHERE sourcelist.SourcePUID = 'MyVariableHere' AND main_small.NAME =  sourcelist.SourceFileName 
GROUP BY `PUID`,`DROID_V`,`SIG_V`,`SPEED` ORDER BY `DROID_V` ASC, `SIG_V` ASC, `SPEED`;