topic Re: ExpandRecordColumn versus ExpandListColumn in Report Server

ExpandRecordColumn versus ExpandListColumn

john_dawson — Wed, 11 Jul 2018 12:52:22 GMT

Problem: when expanding a JSON dataset, programmatically, you can expand a list of Tables using Table.ExpandListColumn, specifying only the column name to be expanded, which is fine. But if you want to expand a list of Records, you seem to have to specify the column names manually. It would be preferable, to have a more generic, less fragile, solution, that would allow you request all columns, without needing to name them, or at least to use a function that could return those column names, before expansion, so to speak. Is this possible?

Re: ExpandRecordColumn versus ExpandListColumn

ImkeF — Wed, 11 Jul 2018 13:06:02 GMT

Hi @john_dawson,

you can use this function instead:

(Table as table, ColumnName as text) =>
Table.ExpandRecordColumn(Table, ColumnName, Record.FieldNames(Table.Column(Table, ColumnName){0}))

It automatically expands all fields of the records that are found in the first rows record.

If the records are different and the names of all records within that column have to be taken into account, you can use this function instead:

= (Table as table, ColumnName as text) =>
Table.ExpandRecordColumn(Table, ColumnName, Record.FieldNames(Record.Combine(Table.Column(Table, ColumnName))))

might be a bit slower then

Re: ExpandRecordColumn versus ExpandListColumn

john_dawson — Wed, 11 Jul 2018 13:38:12 GMT

Neat! Thanks very much, ImkeF

Re: ExpandRecordColumn versus ExpandListColumn

Anonymous — Wed, 28 Aug 2019 15:32:41 GMT

Woo-hoo, thank you! The first function worked for me!