
想通学面须掌复制Initial table: +------+---------+-------+ | id | revenue | month | +------+---------+-------+ | 1 | 8000 | Jan | | 2 | 9000 | Jan | | 3 | 10000 | Feb | | 1 | 7000 | Feb | | 1 | 6000 | Mar | +------+---------+-------+ Result table: +------+-------------+-------------+-------------+-----+-----------+ | id | Jan_Revenue | Feb_Revenue |Mar_Revenue | ... | Dec_Revenue | +------+-------------+-------------+-------------+-----+-----------+ | 1 | 8000 | 7000 | 6000 |... | null | | 2 | 9000 | null | null | ... | null | | 3 | null | 10000 | null | ... | null | +------+-------------+-------------+-------------+-----+-----------+ 1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17.18.