It would definitely help to see what ‘mergetable1’ is, and how you are getting ‘AccelSN’.
If ‘AccelSN’ is read as a string (for example from inputdlg), use the str2double function to get it as a number, since the first column of ‘mergetable1’ is apparently numeric.
For example:
mergetable1 = array2table(randi(9, 10, 3)) % Create Table (To Test Code)
AccelSN = {'4'}; % From ‘inputdlg’
AccelSN = str2double(AccelSN); % Convert To Numeric
BIA0 = mergetable1{AccelSN == mergetable1{:,1},2}
Col_3 = mergetable1{AccelSN == mergetable1{:,1},3}
Please test that with your table and code, since I cannot.
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