If true, throws Exception when result contains more than one row.
Exception if result doesn't contain any rows or if it contains more than one field. Exception if result contains more than one row when throwIfMoreRows is true.
auto cmd = new PGCommand(conn, "SELECT 1"); auto i = cmd.executeScalar!int; // returns int assert(is(typeof(i) == int)); auto v = cmd.executeScalar; // returns Variant
Executes query returning exactly one row and field. By default, returns Variant type.