Hi, i'm a new vb user,
may i ask how to get the max value from the followin situation?
Dataset name: dataset11
Table name: Employee
Column name: StaffID
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
THX!!!
10  17723 
Hi Gene,
You can possibly use DataTable's Select method, but I am not sure it
supports aggregate functions like MAX(). If it doesn't, you should iterate
on all the rows in the DataTable and find out the maximum value in this
column.
To the best of my knowledge, the DataColumn class itself does not provide
such functionality so there is nothing that could replace the "???????"
placeholder in your example.
--
Dmitriy Lapshin [C# / .NET MVP]
X-Unity Test Studio http://x-unity.miik.com.ua/teststudio.aspx
Bring the power of unit testing to VS .NET IDE
"Gene" <eu*******@hotm ail.com> wrote in message
news:u5******** *****@TK2MSFTNG P09.phx.gbl... Hi, i'm a new vb user,
may i ask how to get the max value from the followin situation?
Dataset name: dataset11
Table name: Employee
Column name: StaffID
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
THX!!!
thx!!!
I'll try on that
"Dmitriy Lapshin [C# / .NET MVP]" <x-****@no-spam-please.hotpop.c om> ???
news:eR******** ******@TK2MSFTN GP09.phx.gbl ???... Hi Gene,
You can possibly use DataTable's Select method, but I am not sure it
supports aggregate functions like MAX(). If it doesn't, you should iterate
on all the rows in the DataTable and find out the maximum value in this
column.
To the best of my knowledge, the DataColumn class itself does not provide
such functionality so there is nothing that could replace the "???????"
placeholder in your example.
--
Dmitriy Lapshin [C# / .NET MVP]
X-Unity Test Studio
http://x-unity.miik.com.ua/teststudio.aspx
Bring the power of unit testing to VS .NET IDE
"Gene" <eu*******@hotm ail.com> wrote in message
news:u5******** *****@TK2MSFTNG P09.phx.gbl... Hi, i'm a new vb user,
may i ask how to get the max value from the followin situation?
Dataset name: dataset11
Table name: Employee
Column name: StaffID
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
THX!!!
"Gene" <eu*******@hotm ail.com> wrote in message
news:u5******** *****@TK2MSFTNG P09.phx.gbl... Hi, i'm a new vb user,
may i ask how to get the max value from the followin situation?
Dataset name: dataset11
Table name: Employee
Column name: StaffID
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
This question will be better answered by the ADO.NET group. However, I
*think* you can accomplish this two ways:
1) select an aggregate of the desired column in your actual SQL statement:
SELECT MAX( StaffID ) FROM [Employee]
GROUP BY {add your grouping fields here}
That will return 1 column, with the max values based on your grouping.
2) (not sure if this will work or not)Try using the MAX function in the
select query on the DataSet:
dataset11.Selec t("SELECT MAX(StaffID) FROM [EMPLOYEE]...")
This is the same as the previous method, but it all executes client side,
wich is much better in terms of server abuse. I think it returns either a
DataRowView, or a DataRow( ). If you are having problems with this method,
check the documentation on the DataSet.Select( ) method.
HTH,
Jeremy
Hi Gene,
I am curious, why do you not just use a dataview?
something as rough written
\\\
dv as new dataview(datase t11.employee)
dv.sort="StaffI dColumn, ASC"
txtMaxStaffId.t ext=dv(dv.count-1)("StaffID")
///
Cor the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
THX!!!
Hi Jerymy dataset11.Selec t("SELECT MAX(StaffID) FROM [EMPLOYEE]...")
Which version from VB?
:-)) I did try something like this this this morning but could not find it
Cor
Thx, Jeremy
I have another question is how to do it using method?
I know sql statement,
I know how to use select * from table,
but how to use other functions like MAX in the sql statement using vb.net.
do you mind tell me more on this?
"Jeremy Cowles" <jeremy.cowle s[nosp@m]asifl.com> ???
news:6d******** ***********@twi ster.tampabay.r r.com ???... "Gene" <eu*******@hotm ail.com> wrote in message
news:u5******** *****@TK2MSFTNG P09.phx.gbl... Hi, i'm a new vb user,
may i ask how to get the max value from the followin situation?
Dataset name: dataset11
Table name: Employee
Column name: StaffID
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
This question will be better answered by the ADO.NET group. However, I
*think* you can accomplish this two ways:
1) select an aggregate of the desired column in your actual SQL statement:
SELECT MAX( StaffID ) FROM [Employee]
GROUP BY {add your grouping fields here}
That will return 1 column, with the max values based on your grouping.
2) (not sure if this will work or not)Try using the MAX function in the
select query on the DataSet:
dataset11.Selec t("SELECT MAX(StaffID) FROM [EMPLOYEE]...")
This is the same as the previous method, but it all executes client side,
wich is much better in terms of server abuse. I think it returns either a
DataRowView, or a DataRow( ). If you are having problems with this method,
check the documentation on the DataSet.Select( ) method.
HTH,
Jeremy
it's method "1"
"Gene" <eu*******@hotm ail.com> ¦b¶l¥ó
news:uk******** ******@TK2MSFTN GP09.phx.gbl ¤¤¼¶¼g... Thx, Jeremy
I have another question is how to do it using method?
I know sql statement,
I know how to use select * from table,
but how to use other functions like MAX in the sql statement using vb.net.
do you mind tell me more on this?
"Jeremy Cowles" <jeremy.cowle s[nosp@m]asifl.com> ???
news:6d******** ***********@twi ster.tampabay.r r.com ???... "Gene" <eu*******@hotm ail.com> wrote in message
news:u5******** *****@TK2MSFTNG P09.phx.gbl... Hi, i'm a new vb user,
may i ask how to get the max value from the followin situation?
Dataset name: dataset11
Table name: Employee
Column name: StaffID
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
This question will be better answered by the ADO.NET group. However, I
*think* you can accomplish this two ways:
1) select an aggregate of the desired column in your actual SQL
statement:
SELECT MAX( StaffID ) FROM [Employee]
GROUP BY {add your grouping fields here}
That will return 1 column, with the max values based on your grouping.
2) (not sure if this will work or not)Try using the MAX function in the
select query on the DataSet:
dataset11.Selec t("SELECT MAX(StaffID) FROM [EMPLOYEE]...")
This is the same as the previous method, but it all executes client
side, wich is much better in terms of server abuse. I think it returns either
a DataRowView, or a DataRow( ). If you are having problems with this
method, check the documentation on the DataSet.Select( ) method.
HTH,
Jeremy
thx Cor,
it seems to be a good suggestion to use dataview,
but I have never use it,
I'll try it, THX!!!
"Cor" <no*@non.com> ¦b¶l¥ó news:%2******** ********@tk2msf tngp13.phx.gbl ¤¤¼¶
¼g... Hi Gene,
I am curious, why do you not just use a dataview?
something as rough written
\\\
dv as new dataview(datase t11.employee)
dv.sort="StaffI dColumn, ASC"
txtMaxStaffId.t ext=dv(dv.count-1)("StaffID")
///
Cor
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
THX!!!
Gene,
In addition to the other suggestions I find the easiest way is to use the
DataTable.Compu te function.
txtMaxStaffID.t ext = dataset11.Emplo yee.Compute("Ma x(StaffID)", Nothing)
The second parameter is a filter, incase you want to limit the rows that are
applied to the aggregate function.
David Sceppa's book "Microsoft ADO.NET - Core Reference" from MS Press
covers the DataTable.Compu te function along with every thing else in
ADO.NET!
Hope this helps
Jay
"Gene" <eu*******@hotm ail.com> wrote in message
news:u5******** *****@TK2MSFTNG P09.phx.gbl... Hi, i'm a new vb user,
may i ask how to get the max value from the followin situation?
Dataset name: dataset11
Table name: Employee
Column name: StaffID
the syntax is???
txtMaxStaffID.t ext = dataset11.Emplo yee.StaffIDColu mn.????????
THX!!!
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