How to get the number of rows with less than values VB ASP

Question

0.00/5 (No votes)

See more:

hey guys i want to get the number of rows who is the values is less than my labels when
i fix the values and doit like this it work fine:

        con.Open()
        cmd.CommandText = "select * from tblprodinfo where quantity<5 "

 but when i do this

What I have tried:

<pre>        con.Open()
        cmd.CommandText = "select * from tblprodinfo where quantity<'" & cl.Text & "' "
        rdr = cmd.ExecuteReader
        If rdr.HasRows Then
            While rdr.Read
                crit.Text = Val(crit.Text) + 1
            End While

        End If
        con.Close()

its not working propoerly

Posted 24-Mar-17 23:21pm

Member 12919944

Updated 25-Mar-17 0:31am

Add a Solution

3 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2017-03-24T23:40:00

Never do that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.
Start by checking the user input: use Integer.TryParse to convert it to an Integer value:

VB

Dim quant As Integer
If Not Integer.TryParse(cl.Text, quant) Then
    ' Report problem to user
    ...
    Return
End If

Then pass the converted value to SQL via a parameter:

VB

cmd.CommandText = "SELECT * FROM  tblprodinfo WHERE quantity < @QTY"
cmd.Parameters.AddwithValue("@QTY", quant)
rdr = cmd.ExecuteReader

Michael_Davies · Answer 2 · 2017-03-24T23:58:00

Solution 2

Why bother with a DataReader & manually count each row?

VB

con.Open()
   cmd.CommandText = "SELECT COUNT(*) FROM  tblprodinfo WHERE quantity < @QTY"
   cmd.Parameters.AddwithValue("@QTY", quant)
   crit.Text = cmd.ExecuteScalar.Tostring
   con.Close()

Posted 24-Mar-17 23:58pm

Michael_Davies

Updated 24-Mar-17 23:59pm

v2

Comments

Member 12919944 25-Mar-17 6:25am

this code is good dude but still it give me wrong ouput :/ .

Michael_Davies 25-Mar-17 6:41am

Define "wrong output", SQL will count the number of rows matching the condition and return that count, the output cannot therefore be wrong, if it is not what you expected then the condition needs attention.

Do not just say something is wrong, show what you expect and why and the actual result.

Patrice T · Answer 3 · 2017-03-25T00:31:00

You should refine your question !
It is not clear what work and what don't :it work fine and its not working propoerly.
My guess is that you should remove the single quotes "'" in you second query.

Never build an SQL query by concatenating with user inputs, it is named "SQL injection", it is dangerous for your database and error prone.
A single quote in a name and your program crash. If a user input like "Brian O'Conner" can crash your app, it is an SQL injection vulnerability.
SQL injection - Wikipedia[^]
SQL Injection[^]

How to get the number of rows with less than values VB ASP

3 solutions

Solution 1

Solution 2

Solution 3

Add your solution here

Preview 0