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add a new function mapExtractKeyLike
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凌涛
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39322cdbe2
@ -390,5 +390,43 @@ Result:
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└─────────────────────────────┘
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```
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## mapExtractKeyLike {#mapExtractKeyLike}
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**Syntax**
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```sql
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mapExtractKeyLike(map, pattern)
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```
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**Parameters**
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- `map` — Map. [Map](../../sql-reference/data-types/map.md).
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- `pattern` - String pattern to match.
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**Returned value**
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- A map contained elements the key of which matchs the specified pattern. If there are no elements matched the pattern, it will return an empty map.
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**Example**
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Query:
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```sql
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CREATE TABLE test (a Map(String,String)) ENGINE = Memory;
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INSERT INTO test VALUES ({'abc':'abc','def':'def'}), ({'hij':'hij','klm':'klm'});
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SELECT mapExtractKeyLike(a, 'a%') FROM test;
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```
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Result:
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```text
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┌─mapExtractKeyLike(a, 'a%')─┐
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│ {'abc':'abc'} │
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│ {} │
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└────────────────────────────┘
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```
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[Original article](https://clickhouse.com/docs/en/sql-reference/functions/tuple-map-functions/) <!--hide-->
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@ -382,6 +382,141 @@ public:
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bool useDefaultImplementationForConstants() const override { return true; }
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};
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class FunctionExtractKeyLike : public IFunction
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{
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public:
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static constexpr auto name = "mapExtractKeyLike";
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static FunctionPtr create(ContextPtr) { return std::make_shared<FunctionExtractKeyLike>(); }
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String getName() const override
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{
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return name;
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}
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bool isSuitableForShortCircuitArgumentsExecution(const DataTypesWithConstInfo & /*info*/) const override { return true; }
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size_t getNumberOfArguments() const override { return 2; }
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DataTypePtr getReturnTypeImpl(const ColumnsWithTypeAndName & arguments) const override
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{
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if (arguments.size() != 2)
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throw Exception("Number of arguments for function " + getName() + " doesn't match: passed "
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+ toString(arguments.size()) + ", should be 2",
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ErrorCodes::NUMBER_OF_ARGUMENTS_DOESNT_MATCH);
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const DataTypeMap * map_type = checkAndGetDataType<DataTypeMap>(arguments[0].type.get());
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if (!map_type)
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throw Exception{"First argument for function " + getName() + " must be a map",
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ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
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auto key_type = map_type->getKeyType();
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WhichDataType which(key_type);
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if (!which.isStringOrFixedString())
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throw Exception{"Function " + getName() + "only support the map with String or FixedString key",
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ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
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if (!isStringOrFixedString(arguments[1].type))
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throw Exception{"Second argument passed to function " + getName() + " must be String or FixedString",
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ErrorCodes::ILLEGAL_TYPE_OF_ARGUMENT};
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return std::make_shared<DataTypeMap>(map_type->getKeyType(), map_type->getValueType());
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}
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bool useDefaultImplementationForConstants() const override { return true; }
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ColumnPtr executeImpl(const ColumnsWithTypeAndName & arguments, const DataTypePtr & result_type, size_t input_rows_count) const override
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{
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bool is_const = isColumnConst(*arguments[0].column);
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const ColumnMap * col_map = typeid_cast<const ColumnMap *>(arguments[0].column.get());
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//It may not be necessary to check this condition, cause it will be checked in getReturnTypeImpl function
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if (!col_map)
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return nullptr;
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const DataTypeMap * map_type = checkAndGetDataType<DataTypeMap>(arguments[0].type.get());
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auto key_type = map_type->getKeyType();
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auto value_type = map_type->getValueType();
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const auto & nested_column = col_map->getNestedColumn();
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const auto & values_column = col_map->getNestedData().getColumn(1);
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const ColumnString * keys_string_column = checkAndGetColumn<ColumnString>(col_map->getNestedData().getColumn(0));
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const ColumnFixedString * keys_fixed_string_column = checkAndGetColumn<ColumnFixedString>(col_map->getNestedData().getColumn(0));
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FunctionLike func_like;
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//create result data
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MutableColumnPtr keys_data = key_type->createColumn();
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MutableColumnPtr values_data = value_type->createColumn();
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MutableColumnPtr offsets = DataTypeNumber<IColumn::Offset>().createColumn();
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IColumn::Offset current_offset = 0;
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for (size_t row = 0; row < input_rows_count; row++)
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{
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size_t element_start_row = row != 0 ? nested_column.getOffsets()[row-1] : 0;
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size_t element_size = nested_column.getOffsets()[row]- element_start_row;
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ColumnsWithTypeAndName new_arguments;
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ColumnPtr sub_map_column;
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DataTypePtr data_type;
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if (keys_string_column)
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{
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sub_map_column = keys_string_column->cut(element_start_row, element_size);
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data_type = std::make_shared<DataTypeString>();
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}
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else
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{
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sub_map_column = keys_fixed_string_column->cut(element_start_row, element_size);
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data_type =std::make_shared<DataTypeFixedString>(checkAndGetColumn<ColumnFixedString>(sub_map_column.get())->getN());
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}
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size_t col_key_size = sub_map_column->size();
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auto column = is_const? ColumnConst::create(std::move(sub_map_column), std::move(col_key_size)) : std::move(sub_map_column);
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new_arguments = {
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{
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column,
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data_type,
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""
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},
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arguments[1]
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};
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auto res = func_like.executeImpl(new_arguments, result_type, input_rows_count);
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const auto & container = checkAndGetColumn<ColumnUInt8>(res.get())->getData();
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for (size_t row_num = 0; row_num < element_size; row_num++)
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{
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if (container[row_num] == 1)
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{
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auto key_ref = keys_string_column ?
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keys_string_column->getDataAt(element_start_row + row_num) :
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keys_fixed_string_column->getDataAt(element_start_row + row_num);
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auto value_ref = values_column.getDataAt(element_start_row + row_num);
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keys_data->insertData(key_ref.data, key_ref.size);
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values_data->insertData(value_ref.data, value_ref.size);
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current_offset += 1;
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}
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}
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offsets->insert(current_offset);
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}
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auto result_nested_column = ColumnArray::create(
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ColumnTuple::create(Columns{std::move(keys_data), std::move(values_data)}),
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std::move(offsets));
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return ColumnMap::create(result_nested_column);
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}
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};
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}
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void registerFunctionsMap(FunctionFactory & factory)
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@ -391,6 +526,7 @@ void registerFunctionsMap(FunctionFactory & factory)
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factory.registerFunction<FunctionMapKeys>();
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factory.registerFunction<FunctionMapValues>();
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factory.registerFunction<FunctionMapContainsKeyLike>();
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factory.registerFunction<FunctionExtractKeyLike>();
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}
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}
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@ -0,0 +1,23 @@
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The data of table:
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1 {'P1-K1':'1-V1','P2-K2':'1-V2'}
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2 {'P1-K1':'2-V1','P2-K2':'2-V2'}
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3 {'P1-K1':'3-V1','P2-K2':'3-V2'}
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4 {'P1-K1':'4-V1','P2-K2':'4-V2'}
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5 {'5-K1':'5-V1','5-K2':'5-V2'}
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6 {'P3-K1':'6-V1','P4-K2':'6-V2'}
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The results of query: SELECT id, mapExtractKeyLike(map, \'P1%\') FROM map_extractKeyLike_test ORDER BY id;
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1 {'P1-K1':'1-V1'}
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2 {'P1-K1':'2-V1'}
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3 {'P1-K1':'3-V1'}
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4 {'P1-K1':'4-V1'}
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5 {}
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6 {}
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The results of query: SELECT id, mapExtractKeyLike(map, \'5-K1\') FROM map_extractKeyLike_test ORDER BY id;
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1 {}
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2 {}
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3 {}
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4 {}
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5 {'5-K1':'5-V1'}
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6 {}
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@ -0,0 +1,22 @@
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DROP TABLE IF EXISTS map_extractKeyLike_test;
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CREATE TABLE map_extractKeyLike_test (id UInt32, map Map(String, String)) Engine=MergeTree() ORDER BY id settings index_granularity=2;
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INSERT INTO map_extractKeyLike_test VALUES (1, {'P1-K1':'1-V1','P2-K2':'1-V2'}),(2,{'P1-K1':'2-V1','P2-K2':'2-V2'});
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INSERT INTO map_extractKeyLike_test VALUES (3, {'P1-K1':'3-V1','P2-K2':'3-V2'}),(4,{'P1-K1':'4-V1','P2-K2':'4-V2'});
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INSERT INTO map_extractKeyLike_test VALUES (5, {'5-K1':'5-V1','5-K2':'5-V2'}),(6, {'P3-K1':'6-V1','P4-K2':'6-V2'});
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SELECT 'The data of table:';
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SELECT * FROM map_extractKeyLike_test ORDER BY id;
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SELECT '';
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SELECT 'The results of query: SELECT id, mapExtractKeyLike(map, \'P1%\') FROM map_extractKeyLike_test ORDER BY id;';
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SELECT id, mapExtractKeyLike(map, 'P1%') FROM map_extractKeyLike_test ORDER BY id;
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SELECT '';
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SELECT 'The results of query: SELECT id, mapExtractKeyLike(map, \'5-K1\') FROM map_extractKeyLike_test ORDER BY id;';
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SELECT id, mapExtractKeyLike(map, '5-K1') FROM map_extractKeyLike_test ORDER BY id;
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DROP TABLE map_extractKeyLike_test;
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