**Use case**

Comparison between DateTime64 and DateTime / Date types is allowed but the behavior is confusing (it looks like used numerical comparison):

* from one side for zero-precision it works as expected (values compared as datetime-based ones): 

```sql
SELECT toTypeName(dt64) AS dt64_typename, dt64 = dt
FROM 
(
    SELECT 
        toDateTime64(toStartOfInterval(now(), toIntervalSecond(1), 'UTC'), 0, 'UTC') AS dt64,
        toStartOfInterval(now(), toIntervalSecond(1), 'UTC') AS dt
)

/*
┌─dt64_typename────────┬─equals(dt64, dt)─┐
│ DateTime64(0, 'UTC') │                1 │
└──────────────────────┴──────────────────┘
*/
```
* from another side for non-zero-precision its behavior is unexpected if not used explicit type conversion:

```sql
SELECT 
    toTypeName(dt64) AS dt64_typename,
    dt64 = dt,
    toDateTime(dt64) = dt,
    dt64 = toDateTime64(dt, 1, 'UTC')
FROM 
(
    SELECT 
        toDateTime64(toStartOfInterval(now(), toIntervalSecond(1), 'UTC'), 1, 'UTC') AS dt64,
        toStartOfInterval(now(), toIntervalSecond(1), 'UTC') AS dt
)
/*
┌─dt64_typename────────┬─equals(dt64, dt)─┬─equals(toDateTime(dt64), dt)─┬─equals(dt64, toDateTime64(dt, 1, 'UTC'))─┐
│ DateTime64(1, 'UTC') │                0 │                            1 │                                        1 │
└──────────────────────┴──────────────────┴──────────────────────────────┴──────────────────────────────────────────┘
*/
```

**Describe the solution you'd like**
I think this comparison either:
- should be not allowed and throw an exception to ask for user uses explicit conversion
- or make valid implicit conversion relying on datetime/date essence of values

{
        return x->getType()->isIntegerTy() ? (is_signed ? b.CreateICmpSGT(x, y) : b.CreateICmpUGT(x, y)) : b.CreateFCmpOGT(x, y);
    }
};
template <> struct CompileOp<LessOrEqualsOp>
{
    static llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * x, llvm::Value * y, bool is_signed)
    {
        return x->getType()->isIntegerTy() ? (is_signed ? b.CreateICmpSLE(x, y) : b.CreateICmpULE(x, y)) : b.CreateFCmpOLE(x, y);
    }
};
template <> struct CompileOp<GreaterOrEqualsOp>
{
    static llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * x, llvm::Value * y, bool is_signed)
    {
        return x->getType()->isIntegerTy() ? (is_signed ? b.CreateICmpSGE(x, y) : b.CreateICmpUGE(x, y)) : b.CreateFCmpOGE(x, y);
    }
};
#endif
struct NameEquals          { static constexpr auto name = "equals"; };
struct NameNotEquals       { static constexpr auto name = "notEquals"; };
struct NameLess            { static constexpr auto name = "less"; };
struct NameGreater         { static constexpr auto name = "greater"; };
struct NameLessOrEquals    { static constexpr auto name = "lessOrEquals"; };
struct NameGreaterOrEquals { static constexpr auto name = "greaterOrEquals"; };
template <
    template <typename, typename> class Op,
    typename Name>
class FunctionComparison : public IFunction