Question

Is there any easy way in DolphinDB to accomplish what the shift down function does in Python?

Say I have a matrix that is 3x3:

#0 #1 #2
-- -- --
1  4  7 
2  5  8 
3  6  9

I want to shift one row down in a matrix as follow:

#0 #1 #2
-- -- --
        
1  4  7 
2  5  8 

How can this be done in DolphinDB? Thanks for advance

Answer 1

Well the LAG analytic function sort of does this. Assuming you just want to view your data this way, and that the first column provides the ordering, you could use:

SELECT
    LAG(col1) OVER (ORDER BY col1) AS col1,
    LAG(col2) OVER (ORDER BY col1) AS col2,
    LAG(col3) OVER (ORDER BY col1) AS col3
FROM yourTable
ORDER BY col1;