Example for column expression

[hski-bayer]

In documentation for check definition it says column: column to check (can be a string column name or a column expression)

Can you give an example of a column expression? Can this be also a list of columns, so that the check is executed on all these columns?

[ghanse]

Column expression would be any Spark column expression. For example, to check if the length of values in a string column str_col is not greater than 10:

- criticality: error
  check:
    function: is_not_greater_than
    arguments:
      column: char_length(str_col)
      limit: 10

Use for_each_column to apply the same check to multiple columns. There are some examples in the DQX documentation here.