ydb/yql/essentials/tests/s-expressions/suites/ManyInputTables/LengthOfWeakConcatTables.yql

(
#comment
(let mr_source (DataSource 'yt 'plato))
(let x (Read! world mr_source (MrTableConcat (Key '('table (String 'Input1))) (Key '('table (String 'Input2)))) (Void) '()))
(let world (Left! x))
(let tables (Right! x))
(let length (Length tables))
(let mr_sink (DataSink 'yt (quote plato)))
(let world (Write! world mr_sink (Key '('table (String 'Output))) (Just (AsStruct '('value length))) '()))
(let res_sink (DataSink 'result))
(let world (Write! world res_sink (Key) length '()))
(let world (Commit! world mr_sink))
(let world (Commit! world res_sink))
(return world)
)