C# Parameterized Query MySQL with `in` clause

Question

I am in the process of converting several queries which were hard-coded into the application and built on the fly to parameterized queries. I\'m having trouble with one part

Answer 1

You cannot use parameters for an IN clause.

Answer 2

i'd suggest creating a function (assuming that mysql supports user defined functions) to break the parameter apart to return a table.

Answer 3

Since MySQL 4.0 you can use FIND_IN_SET function to create parametrized SQL with 'in clause'.

Your code:

UPDATE TABLE_1 SET STATUS = 4 WHERE ID IN (1, 14, 145, 43);

Changed to use FIND_IN_SET:

UPDATE TABLE_1 SET STATUS = 4 WHERE FIND_IN_SET(ID, 1, 14, 145, 43);

Finally you can use variables to parametrize your query:

var s = "UPDATE TABLE_1 SET STATUS = 4 WHERE FIND_IN_SET(ID, ?)";
var params = "1, 14, 145, 43";

dataSource.Execute(s, params);

See the W3Schools reference and the MySQL Tutorial

Since FIND_IN_SET is a MySQL function it works with every language not just C#.

Answer 4

Old question, but in case anyone comes across this via Google, here's what I use:

int status = 4;  
string ids = "1,14,145,43";      

m.Parameters.AddWithValue("@Status", status);
m.Parameters.AddWithValue("@IDs", ids);

UPDATE TABLE_1 SET STATUS = @Status WHERE FIND_IN_SET(ID, @IDs) > 0;

Note: FIND_IN_SET is a mySQL specific function.

Credit, where credit is due: See this question: Add List<int> to a mysql parameter

Answer 5

You could build up the parametrised query "on the fly" based on the (presumably) variable number of parameters, and iterate over that to pass them in.

So, something like:

List foo; // assuming you have a List of items, in reality, it may be a List<int> or a List<myObject> with an id property, etc.

StringBuilder query = new StringBuilder( "UPDATE TABLE_1 SET STATUS = ? WHERE ID IN ( ?")
for( int i = 1; i++; i < foo.Count )
{   // Bit naive 
    query.Append( ", ?" );
}

query.Append( " );" );

MySqlCommand m = new MySqlCommand(query.ToString());
for( int i = 1; i++; i < foo.Count )
{
    m.Parameters.Add(new MySqlParameter(...));
}

Answer 6

Loop round your list of integers and perform individual updates.

MSSQL 2008 offers table-valued parameters to avoid this issue, I'm not aware of any similar functionality in MySQL.