# the statements:

create database TestECP;

use TestECP;

CREATE TABLE `TestSmall` (
  `Id` char(8) DEFAULT NULL,
  `PZN` char(7) DEFAULT NULL,
  `EVP` decimal(7,2) DEFAULT NULL,
  `HAP` decimal(7,2) DEFAULT NULL,
  `ArtikelBez` varchar(40) DEFAULT NULL,
  `ArtikelText` varchar(26) DEFAULT NULL,
  `Hersteller` char(5) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
;

CREATE TABLE `TestBig` (
  `Id` char(8) DEFAULT NULL,
  `PZN` char(7) DEFAULT NULL,
  `EVP` decimal(7,2) DEFAULT NULL,
  `HAP` decimal(7,2) DEFAULT NULL,
  `ArtikelBez` varchar(40) DEFAULT NULL,
  `ArtikelText` varchar(26) DEFAULT NULL,
  `Hersteller` char(5) DEFAULT NULL
) ENGINE=MyISAM DEFAULT CHARSET=latin1
;

insert into TestSmall values( '1002100', '12',      3.95, 1.83, 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '00020'), 
                            ( '1025266', '3717968', 0.00, 2.90, 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '00020'),
                            ( '1025267', '222',     0.00, 4.45, 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '00020'),
                            ( '1025268', '3717980', 0.00, 6.30, 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '00020'),
                            ( '1025269', '3717997', 0.00, 6.30, 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '00020') ;
                            

insert into TestBig values ( '01000001', '111',     0.00,    18.91,  'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000025', '999999',  82.95,   0.00,   'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000045', '222',     0.00,    383.92, 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000072', '999999',  0.00,    18.32,  'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000110', '999999',  0.00,    0.00,   'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000114', '999999',  13.06,   12.54,  'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000118', '204665',  25.43,   7.87,   'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000120', '999999',  0.00,    0.00,   'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000139', '999999',  11.80,   3.90,   'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367'),
                           ( '01000141', '999999',  0.00,    0.00,   'XXXXXXXXXXXXXXXXXXXXXXXXXXXXX', 'XXXXXXXXXXXXXXXXXXXXXXXX', '36367') ;

# to produce the effect described:
set optimizer_switch='engine_condition_pushdown=on';

select SQL_NO_CACHE   B.PZN, B.ArtikelText  from TestSmall B where exists ( select 1 from TestBig A where A.Hersteller = '36367' and A.PZN = B.PZN) and B.Hersteller = '00020';

# the result in cond_push():
for TestSmall: OK
for TestBig: OK

start scanning TestSmall: OK

1st scanning TestBig:
FIELD-ITEM  [TestECP] [B] [PZN] name=<PZN>

2nd scanning TestBig:
FIELD-ITEM  [TestECP] [B] [PZN] str_length=<2>  str_value=<37>  name=<PZN>

3rd scanning TestBig:
FIELD-ITEM  [TestECP] [B] [PZN] str_length=<7>  str_value=<222    > name=<PZN>

4th scanning TestBig:
FIELD-ITEM  [TestECP] [B] [PZN] str_length=<3>  str_value=<371> name=<PZN>

5th scanning TestBig:
FIELD-ITEM  [TestECP] [B] [PZN] str_length=<7>  str_value=<3717997> name=<PZN>

as you cann see from the INSERT-statement above it is:
1st: is <>,  should have been <12>
2nd: is <2>, should have been <3717968>
3rd: is <222    >, should have been <222>
4th: ia <371>, should have been <3717980>
5th: is <3717997>, this is correct!