MATLAB: How to merge two different tables using the first column in common

Question

A(class double)

[1  7;
 3 15]

B(class double)

[2  9;
 5 10]

C = (A+B)

[1   7   0;
 2   9   0;
 3  15   0;
 4   0   0;
 5   0  10]

Answer 1

A = [1  7;
     3 15]
B = [2  9;
     5 10]
Ca = [A, zeros(size(A,1),1)];
Cb = [B(:,1), zeros(size(B,1),1), B(:,2)];
M1 = union(A(:,1),B(:,1));
M2 = setdiff((1:max(M1))',M1);
M3 = [M2, zeros(size(M2,1),2)];
C = sortrows([Ca; Cb; M3],[1]);