
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  

{
    NameSet names;
    for (const auto & action : key_expr.getActions())
        names.insert(action.node->result_name);
    return names;
}
KeyCondition::KeyCondition(
    const SelectQueryInfo & query_info,
    ContextPtr context,
    const Names & key_column_names,
    const ExpressionActionsPtr & key_expr_,
    bool single_point_,
    bool strict_)
    : key_expr(key_expr_)
    , key_subexpr_names(getAllSubexpressionNames(*key_expr))
    , prepared_sets(query_info.sets)
    , single_point(single_point_)
    , strict(strict_)
{
    for (size_t i = 0, size = key_column_names.size(); i < size; ++i)
    {
        std::string name = key_column_names[i];
        if (!key_columns.count(name))
            key_columns[name] = i;