common rows intersection of table

[Ash]

What join would I use to find the common rows for two tables?
The tables have the exact same columns, table1 will usually be a subset of table2 but I want to check just those rows that overlap between both?

[Ryan Hamilton]

Hi Ash,

It’s not necessary to use joins you can simply use inter. e.g.
`
q)t:([] a:til 10; b:10*til 10)
q)u:([] a:0 4 4 10 9; b:0 0 40 100 90)

q)t
a b
—-
0 0
1 10
2 20
3 30
4 40
5 50
6 60
7 70
8 80
9 90

q)u
a b
——
0 0
4 0
4 40
10 100
9 90

q)t inter u
a b
—-
0 0
4 40
9 90
`

– Ryan

[Author]

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