**Use case**

Workload generation with continuous queries.

**Describe the solution you'd like**

Similar to now() but non-constant.

#include <DataTypes/DataTypeDateTime.h>
#include <Functions/IFunction.h>
#include <Core/DecimalFunctions.h>
#include <Functions/FunctionFactory.h>
#include <Core/Field.h>
#include <Functions/extractTimeZoneFromFunctionArguments.h>
#include <ctime>
namespace DB
{
namespace ErrorCodes
{
    extern const int ILLEGAL_TYPE_OF_ARGUMENT;
    extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
}
namespace
{
class ExecutableFunctionNow : public IExecutableFunction