compare two colums in different spreadsheets in go

i want to compare tow different columns in two different spreadsheets. My first spreadsheet is named "testtabelle" and the other is named "test" the name of the sheets are both "Tabellenblatt1" I want to compare column A @ testtabelle with column A @ test. If the string are equal, i need the value from colum B @ test and copy it into column b @ testtabelle of the same row, where my strings matched. I think i need two loops for every column and a if statement to compare the values.

I'll be glad if someone can help me!

You can use the SpreadsheetApp class to open multiple sheets. Look up openById or openByUrl, either should work. You can then make two spreadsheet objects, get the values of column A and B of each, iterate through to compare, and copy the value of column B if the values of column A match.

One thing to note is you should use getValue and setValue rather than copyTo as I don't think the latter works across separate spreadsheets.

You should end up with something like this:

// gets spreadsheet A and the range of data
ssA = SpreadsheetApp.openById('ID of spreadsheet A');
sheetA = ssA.getSheetByName('name of sheet in ssA');
dataA = sheetA.getRange('A:B').getValues();
// gets spreadsheet B and the range of data
ssB = SpreadsheetApp.openById('ID of spreadsheet B');
sheetB = ssB.getSheetByName('name of sheet in ssB');
dataB = sheetB.getRange('A:B').getValues();

// loops through column A of spreadsheet A & B and compares
for(var i = 0; i > sheetA.getLastRow(); i++){
  // checks to see if ith value in 2nd row is the same
  if dataA[1][i] == dataB[1][i]{
    var value = sheetA.getRange(i+1, 2).getValue();
    // used i+1 because index of range is 1, while index of the data array is 0
    sheetB.getRange(i+1, 2).setValue(value);
  } // end if
} // end i

There's also a similar question answered here.