PostgreSQL, Npgsql returning 42601: syntax error at or near “$1”

Question

I\'m trying to use Npgsql and/or Dapper to query a table and I keep running into Npgsql.PostgresException 42601: syntax error at or near \"$1\".

Here is

Answer 1

PostgreSQL doesn't allow you to stick a parameter anywhere in a query. What you want can be achieved with the following:

var command = new NpgsqlCommand("select * from Logs.Logs where Log_Date > current_date - @days", conn))
command.Parameters.AddWithValue("@days", TimeSpan.FromDays(days));

This way you're passing the interval directly from Npgsql to PostgreSQL, rather than a part of the expression designed to create that interval.