Substitute part of the content
At the difference of the command replace, the command substitute doesn’t replace the whole content of a cell but only a subpart of it. It has the same definition than the function substitute in excel or replace in SQL and .Net
You need to specify in which column to look for, then the substring to be replaced and finally the new value.
case substitute into column 'beta' value 'bar' with value 'foo';
Referring to the content of other columns
It’s possible to use the content of other columns to define the value to be replaced or the value of substitution. In place of the keyword value, you should use the keyword column.
case substitute into column 'beta' column 'alpha' with value 'foo';
case substitute into column 'beta' column 'alpha' with value 'gamma';
case substitute into column 'beta' value 'bar' with column 'gamma';