1#include <Functions/IFunctionImpl.h>
2#include <Functions/FunctionFactory.h>
3#include <DataTypes/DataTypeTuple.h>
4#include <Columns/ColumnTuple.h>
5#include <memory>
6
7
8namespace DB
9{
10
11namespace ErrorCodes
12{
13 extern const int NUMBER_OF_ARGUMENTS_DOESNT_MATCH;
14}
15
16
17/** tuple(x, y, ...) is a function that allows you to group several columns
18 * tupleElement(tuple, n) is a function that allows you to retrieve a column from tuple.
19 */
20
21class FunctionTuple : public IFunction
22{
23public:
24 static constexpr auto name = "tuple";
25
26 static FunctionPtr create(const Context &)
27 {
28 return std::make_shared<FunctionTuple>();
29 }
30
31 String getName() const override
32 {
33 return name;
34 }
35
36 bool isVariadic() const override
37 {
38 return true;
39 }
40
41 size_t getNumberOfArguments() const override
42 {
43 return 0;
44 }
45
46 bool isInjective(const Block &) override
47 {
48 return true;
49 }
50
51 bool useDefaultImplementationForNulls() const override { return false; }
52 bool useDefaultImplementationForConstants() const override { return true; }
53
54 DataTypePtr getReturnTypeImpl(const DataTypes & arguments) const override
55 {
56 if (arguments.size() < 1)
57 throw Exception("Function " + getName() + " requires at least one argument.", ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
58
59 return std::make_shared<DataTypeTuple>(arguments);
60 }
61
62 void executeImpl(Block & block, const ColumnNumbers & arguments, size_t result, size_t /*input_rows_count*/) override
63 {
64 size_t tuple_size = arguments.size();
65 Columns tuple_columns(tuple_size);
66 for (size_t i = 0; i < tuple_size; ++i)
67 {
68 /** If tuple is mixed of constant and not constant columns,
69 * convert all to non-constant columns,
70 * because many places in code expect all non-constant columns in non-constant tuple.
71 */
72 tuple_columns[i] = block.getByPosition(arguments[i]).column->convertToFullColumnIfConst();
73 }
74 block.getByPosition(result).column = ColumnTuple::create(tuple_columns);
75 }
76};
77
78void registerFunctionTuple(FunctionFactory & factory)
79{
80 factory.registerFunction<FunctionTuple>();
81}
82
83}
84