Doubt about the operation of a parameter

[joseprad]

Hello friends:

I have a doubt about the operation of a parameter.

If I create a TMSQuery with the following statement works properly and gives me back a specified number of rows

  SELECT * FROM WHERE tblClientes DP =''

but if you create the senetecia like this:

SELECT * FROM WHERE tblClientes DP =: dp
ParamByName ('dp'). AsString =''

I do not return anything.

Anyone know why?

very grateful
Josep

[AndreyZ]

Hello,

Please specify the following:
- the script to create the tblClientes table;
- the exact version of SDAC. You can learn it from the About sheet of TMSConnection Editor;
- the exact version of your IDE;
- the exact version of SQL Server and client. You can learn it from the Info sheet of TMSConnection Editor.

[joseprad]

Hello,

the script to create the tblClientes table;

CREATE TABLE [TblClients] (
[CodiClient] [CodiComptable] NOT NULL ,
[NomClient] [nvarchar] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[DP] [nvarchar] (9) COLLATE Modern_Spanish_CI_AS NULL ,
[Adressa] [nvarchar] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[Poblacio] [nvarchar] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[AdressaAvisos] [char] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[PoblacioAvisos] [nvarchar] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[NumComptaCte] [nvarchar] (20) COLLATE Modern_Spanish_CI_AS NULL ,
[DiaDePago] [smallint] NULL ,
[Banc] [nvarchar] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[AdresaDelBanc] [nvarchar] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[PoblacioDelBanc] [nvarchar] (30) COLLATE Modern_Spanish_CI_AS NULL ,
[Debeanyanterior] [PreuV] NULL ,
[HaberAnyAnterior] [PreuV] NULL ,
[SaldoAnyAnterior] [PreuV] NULL ,
[Comentari] [ntext] COLLATE Modern_Spanish_CI_AS NULL ,
[Comisionista] [smallint] NULL CONSTRAINT [DF_TblClients_Comisionista] DEFAULT (0),
[AcumulatDebe] [PreuV] NULL ,
[AcumulatHaber] [PreuV] NULL ,
[Saldo] [PreuV] NULL ,
[PreuOperari] [PreuV] NULL ,
[PreuAjudant] [PreuV] NULL ,
[Reclamacions] [smallint] NULL ,
[CostOperari] [PreuV] NULL ,
[CostAjudant] [PreuV] NULL ,
[Correu] [char] (50) COLLATE Modern_Spanish_CI_AS NULL ,
CONSTRAINT [PK_TblClients] PRIMARY KEY CLUSTERED
(
[CodiClient]
) WITH FILLFACTOR = 90 ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

- the exact version of SDAC. You can learn it from the About sheet of TMSConnection Editor;
Version 5.00.0.2 for Delphi 2010

- the exact version of your IDE;
Delphi 2010
- the exact version of SQL Server and client. You can learn it from the Info sheet of TMSConnection
Microsoft SQL Server 08.00.2282
Microsoft OLE DB Provider for SQL Server 06.01.7601

[AndreyZ]

I checked this question in the following environment:

Code: Select all

Windows 7
Delphi 2010 Version 14.0.3513.24210 Architect
SDAC Version 5.00.0.2
Microsoft SQL Server: 08.00.0194
Microsoft OLE DB Provider for SQL Server: 06.01.7600

, and used the following code:

Code: Select all

MSQuery1.SQL.Text := 'SELECT * FROM TblClients WHERE DP=''''';
MSQuery1.Open;

MSQuery1.SQL.Text := 'SELECT * FROM TblClients WHERE DP=:dp';
MSQuery1.ParamByName('dp').AsString := '';
MSQuery1.Open;

There was no difference in the results of both queries. Please check if you can reproduce the problem using the code above. If you can, please try creating a small sample to demonstrate the problem and send it to andreyz*devart*com .