Can't merge tables with error of weird array size limitation, help?

I got two tables, one with training data and one with created features that I want to implement.

Table A has the size 307511x241 and is like so:

>> head(app_train, 3)
ans =
  3×241 table
    SK_ID_CURR    NAME_CONTRACT_TYPE    CODE_GENDER_M    CODE_GENDER_F    FLAG_OWN_CAR etc.
    __________    __________________    _____________    _____________    ____________ 
      100002              0                   1                0               0       etc.
      100003              0                   0                1               0       etc.
      100004              1                   1                0               1       etc.

Table B has the size 307511x36 and is like so:

>> head(polyFeaturesTrain, 3)
ans =
  3×36 table
    Polynomial constant       EXT_SOURCE_1          EXT_SOURCE_1^2        EXT_SOURCE_1^3   etc.
    ___________________    __________________    ___________________    __________________ 
             1             0.0830369673913226    0.00689513795354757    0.0005725513454074 etc.
             1              0.311267311381222     0.0968873391344949    0.0301578615592749 etc.
             1              0.505997930505754      0.256033905676106     0.129552626411415 etc.

5 variables in Table B are the same as in Table A (EXT_SOURCE_1, EXT_SOURCE_2, EXT_SOURCE_3, DAYS_BIRTH and TARGET). The values for TARGET are the same in both tables, while for the other variables there are some missing values in Table A but not in Table B.

I want to merge Table B into Table A (rows stay the same, only add the variables) and for identical variables want to keep the values from Table B. I tried innerjoin, outerjoin, join and some different Name-Value Pair Arguments for those functions, nothing works. Also trying TableC = [TableA, TableB] doesn't work because of the identical variables.

When using the function I often get this error message:

Error using tabular/outerjoin (line 228)
Requested 1x80527655221 (600.0GB) array exceeds maximum array size preference. Creation of arrays greater than this limit may take a long time and cause MATLAB to become
unresponsive.

The table I want would be 307511x272, how can it be 600GB? I don't understand what Matlab is trying to tell me.

If someone knows what I am doing wrong, please help me out, I spent the last few hours making no progress because of this.

Answer 1

[Stephen23]

"I want to merge Table B into Table A (rows stay the same, only add the variables) and for identical variables want to keep the values from Table B"

x = randi(9,7,1);
y = randi(9,7,1);
z = randi(9,7,1);
A = table(x,y)

A = 7×2 table
    x    y
    _    _

    4    6
    1    7
    1    9
    8    1
    1    3
    2    5
    8    7

y = round(y/2);
B = table(y,z)

B = 7×2 table
    y    z
    _    _

    3    4
    4    5
    5    4
    1    4
    2    2
    3    4
    4    3

V = setdiff(A.Properties.VariableNames,B.Properties.VariableNames);
C = [A(:,V),B]

C = 7×3 table
    x    y    z
    _    _    _

    4    3    4
    1    4    5
    1    5    4
    8    1    4
    1    2    2
    2    3    4
    8    4    3

[Konstantin Maier]

Thank you, that worked!