How to create table with 2D function values?

Question

Consider some function f[x,y]. I want to create a table in the form

table = {{x1,y1,f[x1,y1]},{x1,y2,f[x1,y2]},...,{x2,y1,f[x2,y1]},{x2,y2,f[x2,y2]},...},

where $x_{i},x_{i+1}$ and $y_{i},y_{i+1}$ are separated by some distances $\Delta x$, $\Delta y$, and i ranges from 1 to some N.

The only way I know is to manually create a table

table=Join[Table[{x1,y,f[x1,y]},{y,y1,yN,Deltay}],Table[{x2,y,f[x2,y]},{y,y1,yN,Deltay}],...] 

However, this is not a smart way, especially for large N. Could you please provide some smarter way to build the table?

Answer 1

x1 = 1; xN = 9; Δx = 3;
y1 = 0; yN = 5; Δy = 1;

table = Join @@ Table[{i, j, f[i, j]}, {i, x1, xN, Δx}, {j, y1, yN, Δy}] 

{{1, 0, f[1, 0]}, {1, 1, f[1, 1]}, {1, 2, f[1, 2]}, {1, 3, f[1, 3]}, {1, 4, f[1, 4]}, {1, 5, f[1, 5]},
{4, 0, f[4, 0]}, {4, 1, f[4, 1]}, {4, 2, f[4, 2]}, {4, 3, f[4, 3]}, {4, 4, f[4, 4]}, {4, 5, f[4, 5]},
{7, 0, f[7, 0]}, {7, 1, f[7, 1]}, {7, 2, f[7, 2]}, {7, 3, f[7, 3]}, {7, 4, f[7, 4]}, {7, 5, f[7, 5]}}

Also

table2 = {##, f @ ##} & @@@ Tuples[{Range[x1, xN, Δx], Range[y1, yN, Δy]}]
table2 == table

True

Answer 2

This would be a nice answer (using the Outer product to create the 2D array):

x1 = 1; xN = 9; dx = 3;
y1 = 0; yN = 5; dy = 1; 
Partition[Flatten[
    Outer[Through[{List, f}[#1, #2]] &, Range[x1, xN, dx], Range[y1, yN, dy]]], 3]

except that Outer returns too many levels -- hence the Flatten and Partition are needed to remove the extra brackets. Answer is the same as kglr's.