blob: aea64c8d4ad75f47dcc01610796adf225ae5a172 (
plain) (
blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
|
#include <Functions/IFunction.h>
#include <Functions/FunctionFactory.h>
#include <DataTypes/DataTypeNullable.h>
#include <Columns/ColumnNullable.h>
#include <Core/ColumnNumbers.h>
namespace DB
{
namespace
{
/// If value is not Nullable or NULL, wraps it to Nullable.
class FunctionToNullable : public IFunction
{
public:
static constexpr auto name = "toNullable";
static FunctionPtr create(ContextPtr)
{
return std::make_shared<FunctionToNullable>();
}
std::string getName() const override
{
return name;
}
size_t getNumberOfArguments() const override { return 1; }
bool useDefaultImplementationForNulls() const override { return false; }
bool useDefaultImplementationForNothing() const override { return false; }
bool useDefaultImplementationForConstants() const override { return true; }
bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*arguments*/) const override { return false; }
DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
{
return makeNullable(arguments[0]);
}
ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr &, size_t) const override
{
return makeNullable(arguments[0].column);
}
};
}
REGISTER_FUNCTION(ToNullable)
{
factory.registerFunction<FunctionToNullable>();
}
}
|
