maria-discuss team mailing list archive

[Sergei Golubchik <serg@xxxxxxxxxxx>]

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 security@xxxxxxxxxxx
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