MySQL中decimal类型用法的简单介绍

类型说明 取值范围（MySQL < 3.23） 取值范围（MySQL >= 3.23）
DECIMAL(4,1) -9.9 到 99.9 -999.9 到 9999.9
DECIMAL(5,1) -99.9 到 999.9 -9999.9 到 99999.9
DECIMAL(6,1) -999.9 到 9999.9 -99999.9 到 999999.9
DECIMAL(6,2) -99.99 到 999.99 -9999.99 到 99999.99
DECIMAL(6,3) -9.999 到 99.999 -999.999 到 9999.999

@Entity
public class TestEntity extends Model {
  @Column(nullable = true, columnDefinition = "decimal(11,2)")
  public BigDecimal price;
}

 /**
     * 1.mysql-Decimal(9+2,2)对应java-BigDecimal
     * 2.整数部分9位,小数部分2位,小数四舍五入
     * 3.整除部分超过限定位数9位,报错.
     * 4.小数部分超过位数四舍五入截断，保留2位小数
     */
    TestEntity entity = new TestEntity();
    entity.price = new BigDecimal(Double.toString(123456789.12d));
    entity.save();
    // 整数超过9位报错
    /*
entity = new TestEntity();
    entity.price = new BigDecimal(Double.toString(1234567891.123d));
    entity.save();
    */
    entity = new TestEntity();
    entity.price = new BigDecimal(Double.toString(123456789.123d));
    entity.save();
    entity = new TestEntity();
    entity.price = new BigDecimal(Double.toString(123456789.126d));
    entity.save();
    entity = new TestEntity();
    entity.price = new BigDecimal(Double.toString(123456789d));
    entity.save();
    entity = new TestEntity();
    entity.price = new BigDecimal(Double.toString(123456.2355));
    entity.save();
    entity = new TestEntity();
    entity.price = new BigDecimal(Double.toString(123456.2356));
    entity.save();
    entity = TestEntity.find("price = ?", new BigDecimal(Double.toString(123456789.12d))).first();
    System.out.println("查询结果:" + entity.id + ", " + entity.price);