Can anyone help me Rectify this SQL Query................

Reality Strikes

I'm working on an ASP.Net application accessing couple of database tables from AS400 mainframe server database. In the code there's an SQL Query, which seems very complicated to me, the person who did the actual coding is no more with our firm. Right now the query is producing some kinda result which is wrong. So can anyone please help me out in finding what's wrong with the SQL query? The SQL query is attached below:

Me.OdbcSelectCommand2.CommandText =

"SELECT

SAMFILE.STAYP.SCLINT,
SAMFILE.STAYP.SADMHH,
SAMFILE.STAYP.SADMYY,
SAMFILE.STAYP.SADMMM,
SAMFILE.STAYP.SBLDG,
SAMFILE.STAYP.SADMDD,
SAMFILE.STAYP.STRMCD,
SAMFILE.STAYP.STRMHH,
SAMFILE.STAYP.STRMYY,
SAMFILE.STAYP.STRMMM,
SAMFILE.STAYP.STRMDD,
SAMFILE.CLIENTP.CNAME,
SAMFILE.CLIENTP.CRACE1,
SAMFILE.CLIENTP.CRACE2,
SAMFILE.CLIENTP.CRELIG,
SAMFILE.CLIENTP.CSEX,
SAMFILE.CLIENTP.CBTHHH,
SAMFILE.CLIENTP.CBTHYY,
SAMFILE.CLIENTP.CBTHMM,
SAMFILE.CLIENTP.CBTHDD,
SAMFILE.REFSRP.REFSDS,
SAMFILE.STAYP.SMDPM,
SAMFILE.STAYP.SREFRL,
SAMFILE.STAYP.SADRG1,
SAMFILE.STAYP.SADRG2,
SAMFILE.RACETP.RACEDS,
SAMFILE.RELIGP.RELGDS,
SAMFILE.STAYP.SADMAG

FROM

SAMFILE.REFSRP,
SAMFILE.RELIGP,
SAMFILE.RACETP,
{
oj SAMFILE.STAYP
LEFT OUTER "JOIN SAMFILE.CLIENTP
ON SAMFILE.STAYP.SCLINT = SAMFILE.CLIENTP.""CLNT#""
}

WHERE

SAMFILE.REFSRP.REFSCD = SAMFILE.STAYP.SREFRL
AND
SAMFILE.RELIGP.RELGCD = SAMFILE.CLIENTP.CRELIG
AND
SAMFILE.RACETP.RACECD = SAMFILE.CLIENTP.CRACE1"

// After some loop conditions, the OdbcSelectCommand2 is used in 4 concatenations like this.

OdbcSelectCommand2.CommandText = OdbcSelectCommand2.CommandText & " AND (({ fn CONCAT({ fn CONCAT({ fn CONCAT({ fn CONCAT({ fn CONCAT(digits(SADMHH), digits(SADMYY)) }, '-') }, digits(SADMMM)) }, '-') }, digits(SADMDD)) } <= { d '" & End_date_conv & "' })"
OdbcSelectCommand2.CommandText = OdbcSelectCommand2.CommandText & " AND ({ fn CONCAT({ fn CONCAT({ fn CONCAT({ fn CONCAT({ fn CONCAT(digits(STRMHH), digits(STRMYY)) }, '-') }, digits(STRMMM)) }, '-') }, digits(STRMDD)) } >= { d '" & Start_date_conv & "' })"
OdbcSelectCommand2.CommandText = OdbcSelectCommand2.CommandText & " OR ({ fn CONCAT({ fn CONCAT({ fn CONCAT({ fn CONCAT({ fn CONCAT(digits(SADMHH), digits(SADMYY)) }, '-') }, digits(SADMMM)) }, '-') }, digits(SADMDD)) } <= { d '" & End_date_conv & "' })"
OdbcSelectCommand2.CommandText = OdbcSelectCommand2.Comm