create dataframe from two dataframe with some query

Question

I would like to create a new dataframe which query data from two dataframe. e.g. df1 has x,y, df2 has y,z, df3 will map y value to z, then create a x,z dataframe.

import pandas as pd

df1 = pd.DataFrame({
    "x": ["A","B","C"],
    "y": [10, 20, 30],
})

df2 = pd.DataFrame({
    "y": [20, 10, 40],
    "z": ["green", "blue", "green"],
})

print(df1)
print(df2)

expected output:

:    x   y
: 0  A  10
: 1  B  20
: 2  C  30
:     y      z
: 0  20  green
: 1  10   blue
: 2  40  green

:    x   z
: 0  A  blue
: 1  B  green
: 2  C  N/A