MySQL删除重复数据

重复数据如图所示

自关联，保留id最小的那一条，其它的都删除

DELETE t1 
FROM
	invest_year t1,
	invest_year t2 
WHERE
	t1.pro_id = t2.pro_id 
	AND t1.pro_year = t2.pro_year 
	AND t1.id > t2.id;

DELETE语法如下图所示

Double类型转BigDecimal

Double d = new Double(99.99);
BigDecimal b = new BigDecimal(d.toString());
BigDecimal b1 = new BigDecimal("99.99");