[Python] How to Efficiently Find Records Present in Table t1 but Not in t2 in DolphinDB

I have two structurally identical tables t1 and t2 in DolphinDB. I need to find all records that exist in t1 but not in t2, similar to a set difference operation in Python (set(t1) - set(t2)). Example Data

// Table t1
t1 = table(1 2 3 4 as id, `A`B`C`D as name)

// Table t2
t2 = table(2 3 5 as id, `B`C`E as name)


Desired Output

id | name
---|-----
1 | A
4 | D


Attempted Approach I tried using a subquery with NOT IN:

select * from t1 where id not in select id from t2


This works for small datasets, but performance degrades significantly when tables exceed ~100 rows.

Is there a more efficient way to achieve this in DolphinDB? Ideally, a solution optimized for larger datasets (e.g., using joins or built-in functions).Is there a more efficient way to achieve this in DolphinDB? Ideally, a solution optimized for larger datasets (e.g., using joins or built-in functions).

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