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Properly check distinct columns.

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This commit is contained in:
Nikolai Kochetov 2020-11-26 11:50:02 +03:00
parent 42399e8866
commit 4c09880bc4
1 changed files with 9 additions and 9 deletions
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18
src/Processors/QueryPlan/DistinctStep.cpp
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@ -8,16 +8,16 @@ namespace DB
static bool checkColumnsAlreadyDistinct(const Names & columns, const NameSet & distinct_names)
{
bool columns_already_distinct = true;
if (columns.size() != distinct_names.size()) {
columns_already_distinct = false;
} else {
for (const auto & name : columns)
if (distinct_names.count(name) == 0)
columns_already_distinct = false;
}
if (distinct_names.empty())
return false;
return columns_already_distinct;
/// Now we need to check that distinct_names is a subset of columns.
std::unordered_set<std::string_view> columns_set(columns.begin(), columns.end());
for (const auto & name : distinct_names)
if (columns_set.count(name) == 0)
return false;
return true;
}
static ITransformingStep::Traits getTraits(bool pre_distinct, bool already_distinct_columns)