How to use variable in SQL from powershell script - powershell

Question

I am trying to run a SQL from Power Shell(which is on my windows 7 64 bit desktop) and the remote database host is MS SQL Server 2012.
The code is:
$var1 = 'string';
function Get-ODBC-Data{
param(
[string]$query=$('
SELECT COUNT(*)
FROM [master].[sys].[table_name]
WHERE col2 = ''$var1''
;
'),
[string]$username='db_user_name',
[string]$password='db_password'
)
$conn = New-Object System.Data.Odbc.OdbcConnection
$conn.ConnectionString = "DRIVER={SQL Server};Server=123.456.78.90;Initial Catalog=master;Uid=$username;Pwd=$password;"
$conn.open()
$cmd = New-object System.Data.Odbc.OdbcCommand($query,$conn)
$ds = New-Object system.Data.DataSet
(New-Object system.Data.odbc.odbcDataAdapter($cmd)).fill($ds) | out-null
$conn.close()
$ds.Tables[0]
}
$result = Get-ODBC-Data
Write-Host "SQL_Output: " $result[0];
If I use 'string' in the SQL's where clause instead of $var1 then te script works fine and gives expected result.
Quetion
But I want to be able to pass any string as $var1 to the script as parameter. Then use it in the where clause of the SQL. How can I achieve this?
What I tried
I have tried to enclose $var1 in 1,2 or 3 single quotes in the where clause in attempt to escape the single quote. Also tried adding/removing single quote from 'string' when $var1 is assigned value. I did try [string]$var1 = 'string' as well but none of these worked and I keep getting error mostly related to SQL syntax.

Answer 1

Try this:
function Get-ODBC-Data{
param(
[string]$query=$("
SELECT COUNT(*)
FROM [master].[sys].[table_name]
WHERE col2 = '$($var1)'
;
"),
[string]$username='db_user_name',
[string]$password='db_password'
)
$conn = New-Object System.Data.Odbc.OdbcConnection
$conn.ConnectionString = "DRIVER={SQL Server};Server=123.456.78.90;Initial Catalog=master;Uid=$username;Pwd=$password;"
$conn.open()
$cmd = New-object System.Data.Odbc.OdbcCommand($query,$conn)
$ds = New-Object system.Data.DataSet
(New-Object system.Data.odbc.odbcDataAdapter($cmd)).fill($ds) | out-null
$conn.close()
$ds.Tables[0]
}
$result = Get-ODBC-Data
Write-Host "SQL_Output: " $result[0];
The following runs fine on my setup, and shows the correct results:
$var1 = "test22"
function Get-ODBC-Data{
param(
[string]$query=$("
SELECT COUNT(*)
FROM [master].[sys].[table_name]
WHERE col2 = '$($var1)'
;
"),
[string]$username='db_user_name',
[string]$password='db_password'
)
return $query
}
$result = Get-ODBC-Data
Write-Host " ################### Query ######################## "
Write-Host $result
However, you may have a much easier time just passing the entire query into the function as a parameter rather than just one variable part of the query.
Or setting it inside the function and passing $var1 as a mandatory parameter like so:
function Get-ODBC-Data{
param(
[parameter(Mandatory=$true)][string]$var1,
[string]$username='db_user_name',
[string]$password='db_password'
)
$query="
SELECT COUNT(*)
FROM [master].[sys].[table_name]
WHERE col2 = '$($var1)'
;"
return $query
}
$result = Get-ODBC-Data -var1 "working"
Write-Host " ################### Query ######################## "
Write-Host $result