Paramaterising SQL in SSIS - sql

Question

I'm trying to paramaterize some queries in SSIS. After some reading, it sounds like my best option is to create one variable that contains my base sql, another that contains my criteria and a final variable that is evaluated as an expression that includes both of these. I want to end up with an SQL query that is effectively
UPDATE mytable set something='bar' where something_else='foo'
So my first two variables have the scope of my package and are as follows:
Name: BaseSQL
Data Type: String
Value: UPDATE mytable set something = 'bar' where something_else =
Name: MyVariable
Data Type: String
Value: foo
My third variable has a scope of the data flow task where I want to use this SQL and is as follows:
Name: SQLQuery
Data Type: String
Value: #[User::BaseSQL] + "'" + #[User::MyVariable] + "'"
EvaluateAsExpression: True
In the OLE DB Source, I then choose my connection and 'SQL command from variable' and select User::SQLQuery from the dropdown box. The Variable Value window then displays the following:
#[User::BaseSQL] + "'" + #[User::MyVariable] + "'"
This is as desired, and would provide the output I want from my DB.
The variable name dropdown also contains User::BaseSQL and User::MyVariable so I believe that my namespaces are correct.
However, when I then click preview, I get the following error when configuring an OLE DB Source (using SQL command from variable):
TITLE: Microsoft Visual Studio
Error at Set runtime in DB [Set runtime in myDb DB [1]]: SSIS Error Code DTS_E_OLEDBERROR. An OLE DB error has occurred. Error code: 0x80040E14.
An OLE DB record is available. Source: "Microsoft SQL Server Native Client 10.0" Hresult: 0x80040E14 Description: "Statement(s) could not be prepared.".
An OLE DB record is available. Source: "Microsoft SQL Server Native Client 10.0" Hresult: 0x80040E14 Description: "Must declare the scalar variable "#".".
(Microsoft Visual Studio)
Can anyone advise what I'm missing or how I can resolve this please ?
Thanks in advance!

Answer 1

I had a similar issue.
It seems to be that the designer wants something at design time.
I was getting the error when i tried to click OK on the oleDBSource task after choosing a variable name.
I had a similar situation where the where clause logic was a bit involved and required a script task to assign its value.
This is what things looked like at design time.
#basesql = "select from mytable where "
#where = empty string
#fullsql = #basesql + #where
i was getting the E14 error you mentioned above.
by changing the design time value of #where to something silly, the oleDBSource task got what it wanted and let me use the variable.
#where = " value1 is null and value2 = 'easteregg' "
Related issue, to even get the thing to work, i had to start out by putting a basic select stmt into the sql command so it could go get source columns.
It makes sense, but that step took me and google a while to figure out.

Answer 2

You should set the Expression property of SQLQuery, instead of the Value property. If you do it correctly, the Variable Value window should show you the result of the expression:
UPDATE mytable set something = 'bar' where something_else = 'foo'

Answer 3

I would create a script task and concatenate the strings into one variable and use that as your source:
Dts.Variables["SQLQuery"].Value = Dts.Variables["BaseSQL"].Value.ToString() +
Dts.Variables["MyVariable"].Value.ToString();
Then, in the advanced properties under the component properties tab, you need to change the ValidateExternalMetadad property to False so SSIS will not try to prevalidate your sql query in your variable which would give you a run time error. Just created a simple package and that seemed to work. Hope this helps.
-Ryan