aggregation

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Published: Aug 10, 2022 License: Apache-2.0 Imports: 9 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source
var ErrEvalUnsupportedOnAggregation = errors.NewKind("Unimplemented %s.Eval(). The code should have used AggregationBuffer.Eval(ctx).")
View Source
var ErrUnsupportedJSONFunction = errors.NewKind("unsupported JSON function: %s")

ErrUnsupportedJSONFunction is returned when a unsupported JSON function is called.

Functions

func NewEmptyGroupConcat

func NewEmptyGroupConcat() sql.Expression

func NewJSONObjectAgg

func NewJSONObjectAgg(key, value sql.Expression) sql.Expression

NewJSONObjectAgg creates a new JSONArrayAgg function.

Types

type Avg

type Avg struct {
	expression.UnaryExpression
}

Avg node to calculate the average from numeric column

func NewAvg

func NewAvg(e sql.Expression) *Avg

NewAvg creates a new Avg node.

func (*Avg) Description

func (a *Avg) Description() string

Description implements sql.FunctionExpression

func (*Avg) Eval

func (a *Avg) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements Expression interface.

func (*Avg) FunctionName

func (a *Avg) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*Avg) IsNullable

func (a *Avg) IsNullable() bool

IsNullable implements Expression interface.

func (*Avg) NewBuffer

func (a *Avg) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer implements Aggregation interface.

func (*Avg) String

func (a *Avg) String() string

func (*Avg) Type

func (a *Avg) Type() sql.Type

Type implements Expression interface.

func (*Avg) WithChildren

func (a *Avg) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type Count

type Count struct {
	expression.UnaryExpression
}

Count node to count how many rows are in the result set.

func NewCount

func NewCount(e sql.Expression) *Count

NewCount creates a new Count node.

func (*Count) Description

func (c *Count) Description() string

Description implements sql.FunctionExpression

func (*Count) Eval

func (c *Count) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (*Count) FunctionName

func (c *Count) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*Count) IsNullable

func (c *Count) IsNullable() bool

IsNullable returns whether the return value can be null.

func (*Count) NewBuffer

func (c *Count) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer for the aggregation.

func (*Count) Resolved

func (c *Count) Resolved() bool

Resolved implements the Expression interface.

func (*Count) String

func (c *Count) String() string

func (*Count) Type

func (c *Count) Type() sql.Type

Type returns the type of the result.

func (*Count) WithChildren

func (c *Count) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type CountDistinct

type CountDistinct struct {
	expression.UnaryExpression
}

CountDistinct node to count how many rows are in the result set.

func NewCountDistinct

func NewCountDistinct(e sql.Expression) *CountDistinct

NewCountDistinct creates a new CountDistinct node.

func (*CountDistinct) Description

func (c *CountDistinct) Description() string

Description implements sql.FunctionExpression

func (*CountDistinct) Eval

func (c *CountDistinct) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (*CountDistinct) FunctionName

func (c *CountDistinct) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*CountDistinct) IsNullable

func (c *CountDistinct) IsNullable() bool

IsNullable returns whether the return value can be null.

func (*CountDistinct) NewBuffer

func (c *CountDistinct) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer for the aggregation.

func (*CountDistinct) Resolved

func (c *CountDistinct) Resolved() bool

Resolved implements the Expression interface.

func (*CountDistinct) String

func (c *CountDistinct) String() string

func (*CountDistinct) Type

func (c *CountDistinct) Type() sql.Type

Type returns the type of the result.

func (*CountDistinct) WithChildren

func (c *CountDistinct) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type First

type First struct {
	expression.UnaryExpression
}

First aggregation returns the first of all values in the selected column. It implements the Aggregation interface.

func NewFirst

func NewFirst(e sql.Expression) *First

NewFirst returns a new First node.

func (*First) Description

func (f *First) Description() string

Description implements sql.FunctionExpression

func (*First) Eval

func (f *First) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expresion interface.

func (*First) FunctionName

func (f *First) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*First) NewBuffer

func (f *First) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer to compute the result.

func (*First) String

func (f *First) String() string

func (*First) Type

func (f *First) Type() sql.Type

Type returns the resultant type of the aggregation.

func (*First) WithChildren

func (f *First) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the sql.Expression interface.

type GroupConcat

type GroupConcat struct {
	// contains filtered or unexported fields
}

func NewGroupConcat

func NewGroupConcat(distinct string, orderBy sql.SortFields, separator string, selectExprs []sql.Expression, maxLen int) (*GroupConcat, error)

func (*GroupConcat) Children

func (g *GroupConcat) Children() []sql.Expression

Children implements the Expression interface.

func (*GroupConcat) Description

func (g *GroupConcat) Description() string

Description implements sql.FunctionExpression

func (*GroupConcat) Eval

func (g *GroupConcat) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (*GroupConcat) FunctionName

func (g *GroupConcat) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*GroupConcat) IsNullable

func (g *GroupConcat) IsNullable() bool

IsNullable implements the Expression interface.

func (*GroupConcat) NewBuffer

func (g *GroupConcat) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer for the aggregation.

func (*GroupConcat) Resolved

func (g *GroupConcat) Resolved() bool

Resolved implements the Expression interface.

func (*GroupConcat) String

func (g *GroupConcat) String() string

func (*GroupConcat) Type

func (g *GroupConcat) Type() sql.Type

Type implements the Expression interface. cc: https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_group-concat for explanations on return type.

func (*GroupConcat) WithChildren

func (g *GroupConcat) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type JSONArrayAgg

type JSONArrayAgg struct {
	expression.UnaryExpression
}

JSON_ARRAYAGG(col_or_expr) [over_clause]

JSONArrayAgg Aggregates a result set as a single JSON array whose elements consist of the rows. The order of elements in this array is undefined. The function acts on a column or an expression that evaluates to a single value. Returns NULL if the result contains no rows, or in the event of an error.

https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_json-arrayagg

see also: https://dev.mysql.com/doc/refman/8.0/en/json.html#json-normalization

func NewJSONArrayAgg

func NewJSONArrayAgg(arg sql.Expression) *JSONArrayAgg

NewJSONArrayAgg creates a new JSONArrayAgg function.

func (*JSONArrayAgg) Description

func (j *JSONArrayAgg) Description() string

Description implements sql.FunctionExpression

func (*JSONArrayAgg) Eval

func (j *JSONArrayAgg) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (*JSONArrayAgg) FunctionName

func (j *JSONArrayAgg) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*JSONArrayAgg) IsNullable

func (j *JSONArrayAgg) IsNullable() bool

IsNullable returns whether the return value can be null.

func (*JSONArrayAgg) IsUnsupported

func (j *JSONArrayAgg) IsUnsupported() bool

IsUnsupported implements sql.FunctionExpression

func (*JSONArrayAgg) NewBuffer

func (j *JSONArrayAgg) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer for the aggregation.

func (*JSONArrayAgg) Resolved

func (j *JSONArrayAgg) Resolved() bool

Resolved implements the Expression interface.

func (*JSONArrayAgg) String

func (j *JSONArrayAgg) String() string

func (*JSONArrayAgg) Type

func (j *JSONArrayAgg) Type() sql.Type

Type returns the type of the result.

func (*JSONArrayAgg) WithChildren

func (j *JSONArrayAgg) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type JSONObjectAgg

type JSONObjectAgg struct {
	// contains filtered or unexported fields
}

JSON_OBJECTAGG(key, value) [over_clause]

JSONObjectAgg Takes two column names or expressions as arguments, the first of these being used as a key and the second as a value, and returns a JSON object containing key-value pairs. Returns NULL if the result contains no rows, or in the event of an error. An error occurs if any key name is NULL or the number of arguments is not equal to 2.

https://dev.mysql.com/doc/refman/8.0/en/aggregate-functions.html#function_json-objectagg

see also: https://dev.mysql.com/doc/refman/8.0/en/json.html#json-normalization

func (JSONObjectAgg) Children

func (j JSONObjectAgg) Children() []sql.Expression

Children implements the Expression interface.

func (JSONObjectAgg) Description

func (j JSONObjectAgg) Description() string

Description implements sql.FunctionExpression

func (JSONObjectAgg) Eval

func (j JSONObjectAgg) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (JSONObjectAgg) FunctionName

func (j JSONObjectAgg) FunctionName() string

FunctionName implements sql.FunctionExpression

func (JSONObjectAgg) IsNullable

func (j JSONObjectAgg) IsNullable() bool

IsNullable implements the Expression interface.

func (JSONObjectAgg) IsUnsupported

func (j JSONObjectAgg) IsUnsupported() bool

IsUnsupported implements sql.UnsupportedFunctionStub

func (JSONObjectAgg) NewBuffer

func (j JSONObjectAgg) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer implements the Aggregation interface.

func (JSONObjectAgg) Resolved

func (j JSONObjectAgg) Resolved() bool

Resolved implements the Expression interface.

func (JSONObjectAgg) String

func (j JSONObjectAgg) String() string

func (JSONObjectAgg) Type

func (j JSONObjectAgg) Type() sql.Type

Type implements the Expression interface.

func (JSONObjectAgg) WithChildren

func (j JSONObjectAgg) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type Last

type Last struct {
	expression.UnaryExpression
}

Last aggregation returns the last of all values in the selected column. It implements the Aggregation interface.

func NewLast

func NewLast(e sql.Expression) *Last

NewLast returns a new Last node.

func (*Last) Description

func (l *Last) Description() string

Description implements sql.FunctionExpression

func (*Last) Eval

func (l *Last) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the sql.Expression interface.

func (*Last) FunctionName

func (l *Last) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*Last) NewBuffer

func (l *Last) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer to compute the result.

func (*Last) String

func (l *Last) String() string

func (*Last) Type

func (l *Last) Type() sql.Type

Type returns the resultant type of the aggregation.

func (*Last) WithChildren

func (l *Last) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the sql.Expression interface.

type Max

type Max struct {
	expression.UnaryExpression
}

Max aggregation returns the greatest value of the selected column. It implements the Aggregation interface

func NewMax

func NewMax(e sql.Expression) *Max

NewMax returns a new Max node.

func (*Max) DebugString

func (m *Max) DebugString() string

func (*Max) Description

func (m *Max) Description() string

Description implements sql.FunctionExpression

func (*Max) Eval

func (m *Max) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (*Max) FunctionName

func (m *Max) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*Max) IsNullable

func (m *Max) IsNullable() bool

IsNullable returns whether the return value can be null.

func (*Max) NewBuffer

func (m *Max) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer to compute the result.

func (*Max) String

func (m *Max) String() string

func (*Max) Type

func (m *Max) Type() sql.Type

Type returns the resultant type of the aggregation.

func (*Max) WithChildren

func (m *Max) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type Min

type Min struct {
	expression.UnaryExpression
}

Min aggregation returns the smallest value of the selected column. It implements the Aggregation interface

func NewMin

func NewMin(e sql.Expression) *Min

NewMin creates a new Min node.

func (*Min) Description

func (m *Min) Description() string

Description implements sql.FunctionExpression

func (*Min) Eval

func (m *Min) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (*Min) FunctionName

func (m *Min) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*Min) IsNullable

func (m *Min) IsNullable() bool

IsNullable returns whether the return value can be null.

func (*Min) NewBuffer

func (m *Min) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer to compute the result.

func (*Min) String

func (m *Min) String() string

func (*Min) Type

func (m *Min) Type() sql.Type

Type returns the resultant type of the aggregation.

func (*Min) WithChildren

func (m *Min) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

type Sum

type Sum struct {
	expression.UnaryExpression
}

Sum aggregation returns the sum of all values in the selected column. It implements the Aggregation interface.

func NewSum

func NewSum(e sql.Expression) *Sum

NewSum returns a new Sum node.

func (*Sum) Description

func (m *Sum) Description() string

Description implements sql.FunctionExpression

func (*Sum) Eval

func (m *Sum) Eval(ctx *sql.Context, row sql.Row) (interface{}, error)

Eval implements the Expression interface.

func (*Sum) FunctionName

func (m *Sum) FunctionName() string

FunctionName implements sql.FunctionExpression

func (*Sum) NewBuffer

func (m *Sum) NewBuffer() (sql.AggregationBuffer, error)

NewBuffer creates a new buffer to compute the result.

func (*Sum) String

func (m *Sum) String() string

func (*Sum) Type

func (m *Sum) Type() sql.Type

Type returns the resultant type of the aggregation.

func (*Sum) WithChildren

func (m *Sum) WithChildren(children ...sql.Expression) (sql.Expression, error)

WithChildren implements the Expression interface.

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