Question

SQL查询的最大值怎么赋给变量

我想在代码里面将SQL查询的最大值赋给变量，然后在界面上显示这个值。具体代码怎么写“select max(TPhyValue) from WS_DATA where ModuleID=@ModuleID ”这个是SQL语句

Answer 1

sqlconnection con =new sqlconnection(链接字符串);con.open();sqldateAdapter sda=new sqldateAdapter("这里面写SQL语句",con);datatable dt=new datatable();sda.fill(dt);string abc=dt.row[0][0].tostring(); 这里abc就已经取到最大值了，你想显示在哪就把它赋值在哪就OK

Answer 2

'获取值
Public Function sql_result(sql As String) As String
Dim conn As New ADODB.Connection
Dim rs As New ADODB.Recordset
Set conn = CreateObject("adodb.connection")
conn.Provider = "Microsoft.Jet.OLEDB.4.0"
conn.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + App.Path + "\数据库.mdb;Jet OLEDB:Database Password=123"
rs.Open sql, conn, adOpenStatic, adLockOptimistic
conn.Execute (sql)
sql_result = rs(0).Value
conn.Close
End Function '显示在界面上dim sqlstr as stringsqlstr ="select max(TPhyValue) from WS_DATA where ModuleID=@ModuleID "label1.caption=sql_result(sqlstr )

Answer 3

var Max_V: Integer;ADOquery.Close;ADOQuery.Clear;ADOQuery.SQL.Text:= “select max(TPhyValue) max_v from WS_DATA where ModuleID=@ModuleID ”;ADOQuery.Open;Max_V:= ADOQuery.FieldByName('max_v').AsInteger 。

Answer 4

declare @a varchar(50)
set @a=2
select @a=max(TPhyValue) from WS_DATA where ModuleID=@ModuleID
select @aset @a=10select @a