PL-300 Prepare the data Practice Question

Answer analysis

Option-by-option breakdown

For each option: why learners choose it and why it is or isn't the right answer here.

• ✓

  Use 'Replace Values' to replace null with 0

  Why this is correct

  Replace Values is the correct, direct transformation because it performs an in-place, column-wise substitution of nulls with 0 in a single Power Query step. It targets the actual null placeholder (not an error) and is applied to all selected columns simultaneously, making it the most efficient and unambiguous method for this exact requirement.

• ✗

  Use 'Replace Errors' with value 0

  Why it's wrong here

  Replace Errors is designed to handle error values such as #ERROR or custom error records that arise from data-loading or calculation failures, not nulls. Since nulls represent the intentional absence of a value rather than a malformed expression, this command will leave the null cells untouched, so the resulting column would still contain nulls instead of 0.

• ✗

  Use 'Fill Down' to propagate previous values

  Why it's wrong here

  Fill Down is an imputation strategy that copies the most recent non-null value down to subsequent null cells, potentially producing a sequence of varying numbers rather than a uniform replacement with 0. This approach changes the data semantics by pulling values from unrelated rows and can be misleading if the prior value is not 0, whereas the requirement is a fixed substitution.

• ✗

  Add a custom column with an if statement

  Why it's wrong here

  Adding a custom column with an if statement creates a new column (e.g., Column1 = if [Column] = null then 0 else [Column]) rather than modifying the original column, leaving the source data unchanged unless you also remove or overwrite it. This introduces an unnecessary extra column and M code, consuming more memory and steps than the single Replace Values command, which directly transforms the existing column in place.