Description:
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Using bindParam and named arguments in an insert statement or stored procedure call I can't find a way of inserting or updating fields with a null value.

I think I am using the correct code below according to the PDO documentation

I've tried various combinations of values and parameters, but I can't get it to insert a null value.

Reproduce code:
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SQL:
create table test (c1 int, c2 int);
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PHP:
$cn = new PDO('odbc:DRIVER={Adaptive Server Anywhere 9.0};ENG=webroster;DBN=cct8740;CommLinks=TCP','dba','sql');

//sleep(30);
$dr = $cn->prepare('insert into test(c1,c2) values(:c1, :c2)');
$val1 = 1;
$val2 = 2;
$dr->bindParam(':c1',$val1,PDO_PARAM_INT);
$dr->bindParam(':c2',$val2,PDO_PARAM_NULL);
$dr->execute();


Expected result:
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values 1 and null in the test table

Actual result:
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values 1 and 2 in the test table