Member Avatar for jotae

I'm using Visual Studio c# (spanish)

The code:

cmd.CommandText = "UPDATE cursos SET saldo = saldo - '" + cantidad.ToString() + "' where id = '" + vID + "' ";

vID is a string variable.

The problem is here:

Don't work where id = '" + vID + "' neither where id = '" + vID.ToString() + "'

The error:
(Translating) Don't match data type in criteria expression

saldo working OK.

Can you help me?. Thx.

Edited by jotae because: n/a
  • 3 Contributors
  • 5 Replies
  • 104 Views
  • 9 Hours Discussion Span
  • Latest Post Latest Post by kvprajapati
Member Avatar for Momerath

You are trying to do math with a string saldo = saldo - '" + cantidad.ToString() + "' . If cantidad is a number, then you want saldo = saldo - " + cantidad ... . Leave out the single quotes (') around cantidad.

Edited by Momerath because: n/a
Member Avatar for jotae

Thx but the problem is not in SALDO. This work fine. The problem is in WHERE ID =

Member Avatar for kvprajapati

Use parameterized query to avoid datatype mismatch.

cmd.CommandText = "UPDATE cursos SET saldo = saldo - @cantidad where [id] = @id";
cmd.Parameters.AddWithValue("@cantidad",cantidad);
cmd.Parameters.AddWithValue("@id",vID);
Member Avatar for jotae

thx adatapost!! Solved with parameters. Working fine.

Edited by jotae because: n/a
Member Avatar for kvprajapati

You're welcome!

I'm glad you got it working. Please mark this thread as solved if you have found an answer to your question and good luck!

Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.