两个数据集 分别是
和

输入命令

. use "C:\Users\jiaxuan\Desktop\raplace.dta", clear

. merge 1:1 id y using 2

用2.dta与raplace.dta合并 显示错误结果是：
key variable y is str4 in master but float in using data
    Each key variable -- the variables on which observations are matched --
    must be of the same generic type in the master and using datasets.  Same
    generic type means both numeric or both string.

我哪里错了呢？