1

I'm trying to reference a preceding column c1 in a default value of another column c2 in the xmltable() function, but I get an error: column c1 does not exist.

SELECT * FROM xmltable(
    '.' PASSING '<r/>'
    COLUMNS
    c1 Text PATH 'name()',
    c2 Text DEFAULT c1
);

I wonder why, as this precise usage is permitted by the documentation (emphasis's mine):

If the path expression does not match for a given row but default_expression is specified, the value resulting from evaluating that expression is used. If no DEFAULT clause is given for the column, the field will be set to NULL. It is possible for a default_expression to reference the value of output columns that appear prior to it in the column list, so the default of one column may be based on the value of another column.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.