title: Chart select values from one column based on values in another column (Excel or SigmaPlot)
body: <p>Does anyone know if it's possible to generate a chart  in Excel or SigmaPlot or select values in one column based on the value in another column without having to generate new columns to break out the data.</p>
  
  <p>For example, using the data below I would like a continuous record of 'Date' on the x-axis.  On the y-axis I would like to plot all of the Q data. However, on a secondary axis I would only like to plot the 'T' values that correspond to a 'T-flag' = 1.  Again, if possible, I don't want to have to create any new columns because I have ~80 columns with different variables that I would like to create this type of plot for...</p>
  
  <pre>Date        Q    T    T-flag
  01/01/1981  1.2  2.2  0
  01/02/1981  1.3  2.1  0
  01/03/1981  1.5  3.1  1
  01/04/1981  1.2  2.1  0
  01/05/1981  1.5  3.2  1</pre>