use test;
DROP TABLE IF EXISTS T1;
set @var_0= -1;
set @var_1= -1;
set @var_1= NULL;
set @var_2= CAST(-1 AS SIGNED INTEGER);
set @var_3= CAST(NULL AS SIGNED INTEGER);
set @var_4= CAST(NULL AS UNSIGNED INTEGER);
set @var_5= 'TEXT' ;
SELECT @var_0 as f0, @var_1 as f1, @var_2 as f2,
@var_3 as f3, @var_4 as f4, @var_5 as f5 ;
Catalog	Database	Table	Table_alias	Column	Column_alias	Name	Type	Length	Max length	Is_null	Flags	Decimals	Charsetnr
def					f0	254	20	2	Y	128	31	63
def					f1	254	20	0	Y	128	31	63
def					f2	254	20	2	Y	128	31	63
def					f3	254	8192	0	Y	0	31	8
def					f4	254	8192	0	Y	0	31	8
def					f5	254	8192	4	Y	0	31	8
# As you see the metadataoutput of the (numeric with content NULL) uservariables @var_3, @var_4 
# is similar to @var_5, which was filled with text. But their metadataoutput should equal @var_1.
f0	f1	f2	f3	f4	f5
-1	NULL	-1	NULL	NULL	TEXT
# The written content of the uservariables looks harmless. Therefore the bug looks on the first view not very important.
CREATE TABLE T1 AS 
SELECT @var_0 as f0, @var_1 as f1, @var_2 as f2,
@var_3 as f3, @var_4 as f4, @var_5 as f5 ;
SHOW CREATE TABLE T1;
Table	Create Table
T1	CREATE TABLE `T1` (
  `f0` bigint(20) default NULL,
  `f1` bigint(20) default NULL,
  `f2` bigint(20) default NULL,
  `f3` longtext,
  `f4` longtext,
  `f5` longtext
) ENGINE=MyISAM DEFAULT CHARSET=latin1
# The not intended structure of T1 (f3 and f4 are NOT of type BIGINT or something similar !!) is the result of 
# the wrong properties of @var_3 and @var_4 .
DROP TABLE T1;
CREATE TABLE T1 AS 
SELECT -1 as f0, 
CAST(-1 AS SIGNED INTEGER) as f1,
CAST(NULL AS SIGNED INTEGER) as f2,
CAST(NULL AS UNSIGNED INTEGER) as f3,
'TEXT' as f4;
SHOW CREATE TABLE T1;
Table	Create Table
T1	CREATE TABLE `T1` (
  `f0` int(1) NOT NULL default '0',
  `f1` int(1) NOT NULL default '0',
  `f2` int(0) default NULL,
  `f3` int(0) unsigned default NULL,
  `f4` char(4) NOT NULL default ''
) ENGINE=MyISAM DEFAULT CHARSET=latin1
# If we go the direct way the structure of the table looks acceptable. The interesting columns (now) f2 and f3 have
# the data type int .
# Therefore I speculate the bug is outside of the CAST function and inside of the assignment operation to the uservariable.
DROP TABLE T1;