MySQL 生成一组连续值，用于固定行数，固定数值范围

SELECT DATE_FORMAT(DATE_SUB(NOW(), INTERVAL xc YEAR), '%Y') as date
FROM (
SELECT @xi:=@xi+1 as xc from
(SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5)  xc1,
(SELECT 1 UNION SELECT 2 UNION SELECT 3 UNION SELECT 4 UNION SELECT 5)  xc2,
(SELECT @xi:=-1) xc0
) xcxc