Matlab - Assigning matching variables between two data sets and creating a new table

I'm currently working with two data sets, as shown below:

Data set 1:

Point_ID	Record	Difference (m)
'2804AJGCA57'	'Record003 - 220428_103738_Scanner_1 - 2804AJGCA57'	'0.035240'
'2804AJGCA28'	'Record003 - 220428_103738_Scanner_1 - 2804AJGCA28'	'0.030961'
'2804AJGCA29'	'Record003 - 220428_103738_Scanner_1 - 2804AJGCA29'	'0.030219'

Data set 2:

Point_ID	Easting	Northing	Elevation_OD
'2804AJGCA1'	'200305.3884'	'80809.76627'	'7.25913'
'2804AJGCA2'	'200304.9855'	'80809.20396'	'7.23274'
'2804AJGCA3'	'200304.3783'	'80808.51888'	'7.20207'

Essentially, I need to compare the 1st column of both tables and if the 'Point_ID' from the 2nd data set is found within the 1st, I need to add the 'Difference (m)' column onto the corresponding 'Point_ID' row, in the 2nd data set, or a new table.

I hope that this makes sense. Currently I have the following code:

%% Import CSVs

GCA_data = readtable('Input/Test/GCA&GCP_Results_Flight1.csv', 'Delimiter',';', 'Format','%s %s %s'); %Insert pathway to GCA_Results csv.

XYZ_data= readtable('Input/Test/GCA&GCP_Flight1.csv','Delimiter',',','Format','%s %s %s %s'); %Insert pathway to the GCA XYZ file inputted into RiProcess.


%% Pre - Settings

ids = GCA_data.Object1; %Identifies all points that were used within the GCA calculations

nids = numel(ids); % Identifies the number of unique point ids.

gca_table = [];

for ii = 1:nids; 
   
    ID = ids{ii}; %Speicifies the point ID. 
    
    idx = ismember()
end

Solution

This is a type of join operation. MATLAB can do various different joins on table. See this doc page for more. I'm not sure, but I think you want a "left" join - this is what you need if some entries aren't present, like in this example:

t1 = table(["aaa"; "bbb"; "ccc"], [1; 2; 3], ...
    'VariableNames', {'Point_ID', 'Difference (m)'});
t2 = table(["bbb"; "ccc"; "ddd"], [200; 300; 400], ...
    'VariableNames', {'Point_ID', 'OtherValue'});

% Match up rows by "Point_ID", get "Difference (m)" if
% available and add to "OtherValue". 
% MergeKeys=true means keep only one copy of the key "Point_ID"
outerjoin(t2, t1, type="left", MergeKeys=true)

Which gets:

  3×3 table

    Point_ID    OtherValue    Difference (m)
    ________    __________    ______________

     "bbb"         200               2      
     "ccc"         300               3      
     "ddd"         400             NaN