How do I get a column from an SQLAlchemy result using a column variable?

Question

How can I get at the column of a result if I have a variable for the column? The below is a simplified example. I have a variable that contains the column I want, which will be used in the query. I now want to get the same column from the result.

col_id = some_table.id
query = session.query(col_id)
for row in query:
   id = row ?? col_id

I don't want to have to know the name of the column, as the actual code structure is more like this:

col_id, query = build_query()
for row in query:
  id = row ?? col_id

snakecharmerb · Accepted Answer · 2022-10-01 11:50:41Z

1

You can access it using the key attribute of the column.

for row in query:
    id_ = row[col_id.key]

but this approach is deprecated and will be removed in SQLAlchemy 2.0. The recommended approach is to use the row's _mapping attribute.

for row in query:
    id_ = row._mapping[id_col.key]

or you could output the rows as dictionaries:

for row in query.mappings():
    id_ = row[id_col.key]

answered Oct 1, 2022 at 11:50

snakecharmerb

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