The following procedures should be reviewed:
1. 5 Views are are joined:
DELIMITER //
CREATE OR REPLACE PROCEDURE SQLCPLEX001_13_DN_SHOW_8_Y() CONTAINS SQL
BEGIN
  DECLARE SQLCPLEX001_var INTEGER;
  SELECT STDTBL_COL_1_1 INTO SQLCPLEX001_var FROM SQLCPLEX001_8_DN_SHOW_3_Y, SQLCPLEX001_9_DN_SHOW_4_Y, SQLCPLEX001_10_DN_SHOW_5_Y, SQLCPLEX001_11_DN_SHOW_6_Y, SQLCPLEX001_12_DN_SHOW_7_Y;
END
//                                                                 
DELIMITER ;
2. 5 Tables are joined, STD_TABLE_4 is joined 2 times : 
DELIMITER //
CREATE OR REPLACE PROCEDURE SQLCPLEX001_16_DN_SHOW_12_X()  CONTAINS SQL
BEGIN
    DECLARE SQLCPLEX001_var VARCHAR(11);
    SELECT DISTINCT STD_TABLE_1.COL1, STD_TABLE_2.COL1
    FROM  STD_TABLE_1, STD_TABLE_2
    WHERE STD_TABLE_2.COL1 IN
    (SELECT COL1
      FROM  STD_TABLE_3
      WHERE COL2 = DATE '1999-04-27') AND
            STD_TABLE_1.COL1 IN
              (SELECT COL1
                FROM  STD_TABLE_4
                WHERE STDTBL_COL1_1 = DATE '1999-04-27') AND
                   STD_TABLE_2.COL1 IN
                     (SELECT COL1
                        FROM  STD_TABLE_4
                        WHERE STDTBL_COL1_1 = DATE '1999-04-28') ;
END
//
DELIMITER ;
3. 5 Tables are joined :
DELIMITER //
CREATE OR REPLACE PROCEDURE SQLCPLEX001_15_SHOW_11_X()  CONTAINS SQL
BEGIN
    DECLARE SQLCPLEX001_var VARCHAR(11);
    SELECT STD_TABLE_4.STDTBL_COL1_1, STD_TABLE_1.COL1
        FROM STD_TABLE_1
    INNER JOIN STD_TABLE_2
        ON STD_TABLE_2.COL1 = STD_TABLE_1.COL1
    INNER JOIN STD_TABLE_3
        ON STD_TABLE_3.COL1 = STD_TABLE_2.COL1
    INNER JOIN STD_TABLE_4
        ON STD_TABLE_4.COL1 = STD_TABLE_3.COL1
    INNER JOIN STD_TABLE_5
        ON STD_TABLE_5.COL1 = STD_TABLE_4.COL1;
END
//                           
DELIMITER ;