Wrong implicit cast result

[EPluribusUnum]

Hi *!

row_no_a and row_no_x should be the same: '1'. but without explicit integer cast the result is '1.000000000000000'. ROW_NO is an INTEGER

ROW_NO ROW_NO_A ROW_NO_X
2 1 1.000000000000000

3.0.13, Dialect 1 - Wrong
4.0.6, Dialect 1 - Wrong
5.0.3, Dialect 1 - Wrong

WITH RECURSIVE rowcount (row_no, row_no_a, row_no_x) AS
(
SELECT  1 row_no, CAST('0' AS VARCHAR(2)) row_no_a, CAST('0' AS VARCHAR(20))
FROM rdb$database 
UNION ALL
SELECT  c.row_no + 1, CAST(CAST(c.row_no AS INTEGER) AS VARCHAR(2)), CAST(c.row_no AS VARCHAR(20))
FROM rdb$database 
JOIN rowcount c ON  c.row_no<=1)
SELECT * FROM rowcount WHERE row_no = 2

[mrotteveel]

I wonder if somewhere internally it handles row_no as NUMERIC(18) instead of INTEGER (which is how it is described externally), as in dialect 1, NUMERIC(18) is effectively a DOUBLE PRECISION.

[mrotteveel]

That said, I think this is the behaviour it has always had, and given dialect 1 is deprecated, it is not something that should be changed.