If I understand correctly, by default data.table merges two tables by comparing columns which are set as keys and have same names. How should I write if I have tables with different column names? For example:

set.seed(123)
DT1<-data.table(col1=sample(letters,5,replace=TRUE),col2=sample(LETTERS[1:5],5,replace=TRUE),col3=sample(1:2,5,replace=TRUE))
DT2<-data.table(col4=sample(1:3,10,replace=TRUE),col5=sample(LETTERS[1:5],10,replace=TRUE),col6=sample(1:100,10,replace=TRUE))
(DT1)
(DT2)

> (DT1)
   col1 col2 col3
1:    h    A    2
2:    u    C    1
3:    k    E    2
4:    w    C    2
5:    y    C    1
> (DT2)
    col4 col5 col6
 1:    3    D   48
 2:    1    C   76
 3:    1    C   22
 4:    1    B   32
 5:    3    A   24
 6:    3    E   15
 7:    3    E   42
 8:    2    D   42
 9:    3    D   37
10:    2    A   16

What should I write in DT1[ to make a merge selecting only rows with col2==col5 & col3==col4? Here is an expected output:

   col1 col2 col3 col4 col5 col6
    h    A    2    2    A   16
    u    C    1    1    C   76
    u    C    1    1    C   22
    y    C    1    1    C   76
    y    C    1    1    C   22

Thanks in advance!

r merge data.table
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