SQL add string as a parameter

Question

//cmd.CommandText = @"select MaKH from KHACHHANG where HoTenKH='a'";
cmd.CommandText = @"select MaKH from KHACHHANG where HoTenKH=$tenKH";
cmd.Parameters.Add(new SQLiteParameter("$tenKH", tenKH));

The comment line works, cmd is a DbCommand, I've tried

cmd.CommandText = @"select MaKH from KHACHHANG where HoTenKH='$tenKH'";

But it doesn't work neither.

Are you getting an error message, or are you getting zero results? — egrunin
– egrunin, Commented Jun 21, 2010 at 3:03

egrunin · Accepted Answer · 2010-06-21 03:13:05Z

2

This seems silly, but are you making sure to do this:

string tenKH = "a";

before doing this:

cmd.CommandText = @"select MaKH from KHACHHANG where HoTenKH = @tenKH";
cmd.Parameters.Add(new SQLiteParameter("@tenKH", tenKH));

edited Jun 21, 2010 at 3:13

answered Jun 21, 2010 at 3:05

egrunin

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3 Comments

egrunin Over a year ago

Why the downvote? This is a perfectly reasonable question. And he still hasn't told use what "doesn't work".

Tzu ng Over a year ago

This really makes sense. I pass tenKH = textBox.ToString(); , I change to tenKH = textBox.Text; < Pure string, and it works. Thanks

Tzu ng Over a year ago

@Sorry for wrong vote, you get my best vote, with respect :) I'm a young developer.

Adam Robinson · Accepted Answer · 2010-06-21 01:45:43Z

1

SQLite uses a colon to designate a named parameter, not a dollar sign. Try

cmd.CommandText = @"select MaKH from KHACHHANG where HoTenKH=:tenKH";
cmd.Parameters.Add(new SQLiteParameter("tenKH", tenKH));

You could also use the @ symbol if you want the code to look more like SQL Server code:

cmd.CommandText = @"select MaKH from KHACHHANG where HoTenKH=@tenKH";
cmd.Parameters.Add(new SQLiteParameter("tenKH", tenKH));

answered Jun 21, 2010 at 1:45

Adam Robinson

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4 Comments

Adam Robinson Over a year ago

@nXqd: Did you try a colon instead? See my first example.

Tzu ng Over a year ago

I've tried both ways, HoTenKH in MaKH Table is char(30) , tenKH is a string. Does it cause problem ?

Cylon Cat Over a year ago

I don't know SQLite, but with other databases, the prefix character for the parameter name needs to be used in both the SQL statement and the parameter definition, e.g., new SQLiteParameter(":tenKH", tenKH); // note added colon, or @ sign, whichever you use.

Adam Robinson Over a year ago

@Cylon: It's worth a try. I'm not a SQLite developer, but the examples I saw online omitted the prefix. Note that SqlParameters do not require the prefix.

Brian R. Bondy · Accepted Answer · 2010-06-21 02:38:04Z

1

Use an @ sign instead of $ to prefix your parameter name

edited Jun 21, 2010 at 2:38

answered Jun 21, 2010 at 1:44

Brian R. Bondy

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