
create table test1 (a Float32,  b Float32 ) engine = MergeTree order by a ;
insert into test1 values (0.1,0.1), (0.2,0.2);
select count() from test1 where b = 0.1;
0 
select count() from test1 where b = toFloat32(0.1);
1
select count() from test1 where a > 0;
0
select count() from test1 where a > 0.0;
2
select count() from test1 where b > 0;
2

version 22.1.3.7  

rpn.emplace_back(element);
            }
            return;
        }
    }
    if (!tryParseAtomFromAST(node, context, block_with_constants, element))
    {
        element.function = RPNElement::FUNCTION_UNKNOWN;
    }
    rpn.emplace_back(std::move(element));
}
/** The key functional expression constraint may be inferred from a plain column in the expression.
  * For example, if the key contains `toStartOfHour(Timestamp)` and query contains `WHERE Timestamp >= now()`,
  * it can be assumed that if `toStartOfHour()` is monotonic on [now(), inf), the `toStartOfHour(Timestamp) >= toStartOfHour(now())`
  * condition also holds, so the index may be used to select only parts satisfying this condition.
  *
  * To check the assumption, we'd need to assert that the inverse function to this transformation is also monotonic, however the
  * inversion isn't exported (or even viable for not strictly monotonic functions such as `toStartOfHour()`).
  * Instead, we can qualify only functions that do not transform the range (for example rounding),
  * which while not strictly monotonic, are monotonic everywhere on the input range.
  */
bool KeyCondition::transformConstantWithValidFunctions(
    const String & expr_name,
    size_t & out_key_column_num,
    DataTypePtr & out_key_column_type,
    Field & out_value,
    DataTypePtr & out_type,
    std::function<bool(IFunctionBase &, const IDataType &)> always_monotonic) const
{
    const auto & sample_block = key_expr->getSampleBlock();