Oracle 18c

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CREATE TABLE tab(id INT, d DATE,
                 v1 VARCHAR2(100), v2 VARCHAR2(100), v3 VARCHAR2(100) );




INSERT INTO tab(id, d,v1, v2, v3) 
VALUES (1, SYSDATE, '  aaaa   ', '     b   ', '  c');
1 rows affected

INSERT INTO tab(id, d,v1, v2, v3)
VALUES (2, SYSDATE+1, '   afasd', '    ', '  d');
1 rows affected

SELECT * FROM tab;


ID
D
V1
V2
V3


1
16-APR-24
  aaaa
     b
  c

2
17-APR-24
   afasd
    
  d


CREATE OR REPLACE PACKAGE ptf AS
  FUNCTION describe(tab IN OUT dbms_tf.table_t)RETURN dbms_tf.describe_t;      
  PROCEDURE FETCH_ROWS;
END ptf; 
/
CREATE OR REPLACE PACKAGE BODY  ptf AS
  FUNCTION describe(tab IN OUT dbms_tf.table_t) RETURN dbms_tf.describe_t AS
  new_cols DBMS_TF.COLUMNS_NEW_T;
  BEGIN
    FOR i IN 1 .. tab.column.count LOOP
        IF tab.column(i).description.type IN ( dbms_tf.type_varchar2) THEN
           tab.column(i).pass_through:=FALSE;
           tab.column(i).for_read:= TRUE;
           NEW_COLS(i) :=
              DBMS_TF.COLUMN_METADATA_T(name=> tab.column(i).description.name,
                                       type => tab.column(i).description.type);
        END IF;
    END LOOP;
    RETURN DBMS_TF.describe_t(new_columns=>new_cols, row_replication=>true);
    END;

  PROCEDURE FETCH_ROWS AS
    inp_rs DBMS_TF.row_set_t;
    out_rs DBMS_TF.row_set_t;
    rows   PLS_INTEGER;
  BEGIN 
    DBMS_TF.get_row_set(inp_rs, rows);
    FOR c IN 1 .. inp_rs.count() LOOP
      FOR r IN 1 .. rows LOOP
          out_rs(c).tab_varchar2(r) := TRIM(inp_rs(c).tab_varchar2(r));
      END LOOP;
    END LOOP;
    DBMS_TF.put_row_set(out_rs, replication_factor => 1);
  END;
END ptf; 
/
CREATE OR REPLACE FUNCTION trim_col(tab TABLE)
RETURN TABLE pipelined row polymorphic USING ptf;
/
SELECT *
FROM trim_col(tab);


ID
D
V1
V2
V3


1
16-APR-24
aaaa
b
c

2
17-APR-24
afasd
null
d