**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

{
        c = Op::apply(a.compareAt(0, 0, b, 1), 0);
    }
};
#if USE_EMBEDDED_COMPILER
template <template <typename, typename> typename Op> struct CompileOp;
template <> struct CompileOp<EqualsOp>
{
    static llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * x, llvm::Value * y, bool )
    {
        return x->getType()->isIntegerTy() ? b.CreateICmpEQ(x, y) : b.CreateFCmpOEQ(x, y); 
    }
};
template <> struct CompileOp<NotEqualsOp>
{
    static llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * x, llvm::Value * y, bool )
    {
        return x->getType()->isIntegerTy() ? b.CreateICmpNE(x, y) : b.CreateFCmpONE(x, y);
    }
};
template <> struct CompileOp<LessOp>
{
    static llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * x, llvm::Value * y, bool is_signed)
    {
        return x->getType()->isIntegerTy() ? (is_signed ? b.CreateICmpSLT(x, y) : b.CreateICmpULT(x, y)) : b.CreateFCmpOLT(x, y);
    }
};
template <> struct CompileOp<GreaterOp>
{
    static llvm::Value * compile(llvm::IRBuilder<> & b, llvm::Value * x, llvm::Value * y, bool is_signed)