Hi, Roberto! On Jan 20, Roberto Spadim wrote: > Hi guys! There's a "easy/fast" way to rewrite a query from this: > > Select datetime,key,value from table where ... > > To this: > > Select datetime, value1 as key1, value2 as key2, .... From table where ... > > I don't remember the right name in R/python (pandas) language but it's > something like vector/matrix merge > > The ideia is, instead of one line of date key vale, use a single date, and > "put" values as columns, and the columns name is the key name > > The table structure is something like: > Create table ( > Datetime datetime not null, > Key varchar(255) not null, > Value double not null, > Primary key(datetime,key) > ) > > Any idea is wellcome > I know there's many solutions, if i have >100 columns, if datetime is > sparse (only one key have values per datetime value), etc etc
Check the PIVOT table type of the CONNECT engine. https://mariadb.com/kb/en/mariadb/connect-table-types-pivot-table-type/ Regards, Sergei Chief Architect MariaDB and [email protected] -- Vote for my Percona Live 2016 talks: https://www.percona.com/live/data-performance-conference-2016/sessions/mariadb-connectors-fast-and-smart-new-protocol-optimizations#community-voting https://www.percona.com/live/data-performance-conference-2016/sessions/mariadb-101-security-validation-authentication-encryption#community-voting _______________________________________________ Mailing list: https://launchpad.net/~maria-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-discuss More help : https://help.launchpad.net/ListHelp
