Using BETWEEN operator in a WHERE clause with dates from an internal table - abap

Question

I have an internal table populated with start and end dates for each type of period. I want to use this internal table in a WHERE clause of an SQL query to select items whose start and end dates are within the open period of their respective type.
TYPES: BEGIN OF s_openprd,
TETXT TYPE TETXT,
fromdate TYPE d,
todate TYPE d,
END OF s_openprd.
DATA: it_openprd TYPE TABLE OF s_openprd WITH KEY TETXT.
SELECT * FROM FPLT
INNER JOIN #it_openprd AS OP ON FPLT~TETXT = OP~TETXT
WHERE FPLT~FKDAT BETWEEN OP~fromdate AND OP~todate
AND FPLT~NFDAT BETWEEN OP~fromdate AND OP~todate
However I get the error saying that OP~fromdate should be of a compatible type to be used as an operator with BETWEEN. The types listed include the date type d.
I've tried replacing BETWEEN with regular >= and <= operators:
SELECT * FROM FPLT
INNER JOIN #it_openprd AS OP ON FPLT~TETXT = OP~TETXT
WHERE FPLT~FKDAT >= OP~fromdate AND FPLT~FKDAT <= OP~todate
AND FPLT~NFDAT >= OP~fromdate AND FPLT~NFDAT <= OP~todate
But the query returns incorrect results.
I assume the ABAP type d is incompatible with SQL type d ?
How can I use an internal table to restrict the selection in this way ?

Answer 1

Nothing prevents you from using FOR ALL ENTRIES instead of joining with internal table, if you ABAP version does not support it.
Regarding "incorrect results" I agree with Sandra, BETWEEN and LT/GT have totally identical sense, so it is more a matter of what you expect than correctness. I'd rather utilize standard logic for dealing with the issue that bothers you:
The problem with FPLT-NFDAT and FPLT-FKDAT is that their order is not consistent. In one entry, the value of NFDAT may be anterior to FKDAT and in another entry it's the opposite.
Following the same approach for you SQL query, you can write something like this:
TYPES: BEGIN OF ty_fplt,
fplnr TYPE fplnr,
fkdat TYPE fkdat,
nfdat TYPE nfdat,
END OF ty_fplt,
tt_fplt TYPE STANDARD TABLE OF ty_fplt WITH NON-UNIQUE KEY fkdat nfdat.
DATA(lt_fplt_base) = VALUE tt_fplt( ).
SELECT fplnr, CASE WHEN nfdat < fkdat THEN nfdat ELSE fkdat END AS fkdat,
CASE WHEN nfdat < fkdat THEN fkdat ELSE nfdat END AS nfdat
FROM fplt
INTO TABLE #lt_fplt_base.
SELECT *
FROM fplt AS f
INTO TABLE #DATA(result)
FOR ALL ENTRIES IN #lt_fplt_base
WHERE f~fplnr = #lt_fplt_base-fplnr
AND f~fkdat >= #lt_fplt_base-fkdat
AND f~nfdat <= #lt_fplt_base-nfdat.
Don't take it as a rule of thumb, it is just a quick suggestion.
P.S. Joining by text field INNER JOIN #it_openprd AS OP ON FPLT~TETXT = OP~TETXT does not make sense in any context. Text/string fields are often ambiguous, they often contain control characters, whitespaces, etc., which make them useless for primary key.