You can do:
SELECT * FROM <table> WHERE MATNR IN ( SELECT MATNR FROM :input_table) );
Where the input table contains the list of desired MATNR.
The input table can also be a temporary table.
To call this procedure, you could do something like:
DROP TABLE "#MATNR";
CREATE LOCAL TEMPORARY TABLE "#MATNR" ( "MATNR" VARCHAR(6)
);
INSERT INTO #TYPE VALUES ('100239');
INSERT INTO #TYPE VALUES ('220432');
INSERT INTO #TYPE VALUES ('942210');
CALL <procedure>("#MATNR", ?);
Best regards,
Henrique.