This is because tbcdfield uses the currency data type that has a fixed scale of 4 decimal places Bcd字段类型使用了货币类型,这种类型是小数点后是4位数。
Bcd detail specification for electronic component . semiconductor integrated circuit . type ch2019 4 - line to 10 - line decoder with bcd - in 电子元器件详细规范.半导体集成电路ch2019型4线- 10线译码器