Transpose mysql query rows into columns

问题

I have a simple query that produces the below results:

SELECT month,transporttype,count(transporttype) as loads 
from deliveries 
group by month,transporttype

I would like to transpose the rows into columns.

I understand mysql does not have pivot functions so a union is required but not 100% sure.

Thanks in advance for the help.

回答1:

You can do it with a crosstab like this -

SELECT
    `year`,
    `month`,
    SUM(IF(`transporttype` = 'inbound',                 1, 0)) AS `inbound`,
    SUM(IF(`transporttype` = 'LocalPMB',                1, 0)) AS `LocalPMB`,
    SUM(IF(`transporttype` = 'Long Distance',           1, 0)) AS `Long Distance`,
    SUM(IF(`transporttype` = 'shuttle',                 1, 0)) AS `shuttle`,
    SUM(IF(`transporttype` = 'export',                  1, 0)) AS `export`,
    SUM(IF(`transporttype` = 'Extrusions-LongDistance', 1, 0)) AS `Extrusions-LongDistance`,
    SUM(IF(`transporttype` = 'Extrusions-Shuttle',      1, 0)) AS `Extrusions-Shuttle`
FROM `deliveries`
GROUP BY `year`, `month`

On a different note, you should move transporttype values to a lookup table and have transporttype_id in this table.

来源：https://stackoverflow.com/questions/9685601/transpose-mysql-query-rows-into-columns