How to create a loop for the parameterized sql query

Question

0.00/5 (No votes)

See more:

Hi, I would like to create a looping for the following piece of code.
Anyone can help?

C#

string sql = "SELECT TILE = '" + tile[0]
+ " UNION ALL SELECT tile= '" + tile[1] + "'"
+ " UNION ALL SELECT tile= '" + tile[2] + "'"
+ " UNION ALL SELECT tile= '" + tile[3] + "'"
.
.
.
+ " UNION ALL SELECT tile= '" + tile[n-1] + "'"
+ " UNION ALL SELECT tile= '" + tile[n] + "'";

to make it become like

SQL

string sql1 = "SELECT TILE = '" + tile[0]
+ " UNION ALL SELECT '" + tile[1] + "'"

for i=1;i<100;i++)
{
string sql2 = "UNION ALL SELECT tile = tile[i+1];
string sql = sql1+sql2;
}

If i did the loop as shown, it is able to print only the last tile (input from textbox ).
Anyone can help on this?

Posted 6-Jul-15 20:02pm

Member 11765602

Add a Solution

3 solutions

Solution 1

You don't have to create more variables, you can simply assign it like

C#

for i=1;i<100;i++)
{
    sql1 += "UNION ALL SELECT tile = '" + tile[i+1] + "';";
}

Make sure you are using proper value for the loop counter.

Posted 6-Jul-15 20:26pm

Shanish K

Updated 6-Jul-15 20:28pm

v2

Solution 3

Probably a shorter and simple version could be like

C#

string sql = "SELECT TILE = '" + string.Join("' UNION ALL SELECT TILE = '", tile)

Posted 6-Jul-15 22:51pm

_Asif_

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 · Accepted Answer · 2015-07-06T20:31:00

Um...There are a few things wrong there.
The one you have noticed is simple:

C#

for i=1;i<100;i++)
{
string sql2 = "UNION ALL SELECT tile = tile[i+1];
string sql = sql1+sql2;
}

Will always exist with the same string, because each time round the loop you overwrite the previous content of sql and sql2 instead of adding to them.
Probably, what you want is closer to:

C#

for i=1;i<100;i++)
{
string sql2 = "UNION ALL SELECT tile = tile[i+1];
string sql1 += sql2;
}
sql += sql1;

But that won't work either because:
1) You are missing the end double quote!
2) You need a space to separate the UNION parts:

C#

for i=1;i<100;i++)
{
string sql2 = " UNION ALL SELECT tile = tile[i+1]";
string sql1 += sql2;
}
sql += sql1;

1) you need a number not a string:

C#

for i=1;i<100;i++)
{
string sql2 = string.Format(" UNION ALL SELECT tile = tile[{0}]", i + 1);
string sql1 += sql2;
}
sql += sql1;

But if you are going to do things like that, I'd strongly suggest you start looking at using a StringBuilder instead of string concatenation!