expressions

package
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 Go to latest Published: Sep 7, 2015 License: Apache-2.0 Imports: 28 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	// BuiltinFuncDatabase is the keyword for Database function.
	BuiltinFuncDatabase = "database"
	// BuiltinFuncIf is the keyword for If function.
	BuiltinFuncIf   = "if"
	BuiltinFuncLeft = "left"
)

Builin functions entry key with name conflict with keywords.

View Source 
const (
	// ExprEvalFn is the key saving Call expression.
	ExprEvalFn = "$fn"
	// ExprEvalArgCtx is the key saving Context for a Call expression.
	ExprEvalArgCtx = "$ctx"
	// ExprAggDone is the key indicating that aggregate function is done.
	ExprAggDone = "$aggDone"
	// ExprEvalArgAggEmpty is the key to evaluate the aggregate function for empty table.
	ExprEvalArgAggEmpty = "$agg0"
	// ExprEvalDefaultName is the key saving default column name for Default expression.
	ExprEvalDefaultName = "$defaultName"
	// ExprEvalIdentFunc is the key saving a function to retrieve value for identifier name.
	ExprEvalIdentFunc = "$identFunc"
	// ExprEvalPositionFunc is the key saving a Position expresion.
	ExprEvalPositionFunc = "$positionFunc"
	// ExprAggDistinct is the key saving a distinct aggregate.
	ExprAggDistinct = "$aggDistinct"
	// ExprEvalValuesFunc is the key saving a function to retrieve value for column name.
	ExprEvalValuesFunc = "$valuesFunc"
)

Variables

View Source 
var (
	// CurrentTimestamp is the keyword getting default value for datetime and timestamp type.
	CurrentTimestamp = "CURRENT_TIMESTAMP"
	// CurrentTimeExpr is the expression retireving default value for datetime and timestamp type.
	CurrentTimeExpr = &Ident{model.NewCIStr(CurrentTimestamp)}
	// ZeroTimestamp shows the zero datetime and timestamp.
	ZeroTimestamp = "0000-00-00 00:00:00"
)

Functions

func ContainAggregateFunc 

func ContainAggregateFunc(e expression.Expression) bool

ContainAggregateFunc checks whether expression e contains an aggregate function, like count(*) or other.

func Eval 

func Eval(v expression.Expression, ctx context.Context, env map[interface{}]interface{}) (y interface{})

Eval is a helper function evaluates expression v and do a panic if evaluating error.

func EvalBoolExpr 

func EvalBoolExpr(ctx context.Context, expr expression.Expression, m map[interface{}]interface{}) (bool, error)

EvalBoolExpr evaluates an expression and convert its return value to bool.

func Expr 

func Expr(v interface{}) expression.Expression

Expr removes parenthese expression, e.g, (expr) -> expr.

func FastEval 

func FastEval(v interface{}) interface{}

FastEval evaluates Value and static +/- Unary expression and returns its value.

func GetTimeValue 

func GetTimeValue(ctx context.Context, v interface{}, tp byte, fsp int) (interface{}, error)

GetTimeValue gets the time value with type tp.

func IsCurrentTimeExpr 

func IsCurrentTimeExpr(e expression.Expression) bool

IsCurrentTimeExpr returns whether e is CurrentTimeExpr.

func IsQualified 

func IsQualified(name string) bool

IsQualified returns whether name contains ".".

func Lookup 

func Lookup(label string) (e encoding.Encoding, name string)

Lookup returns the encoding with the specified label, and its canonical name. It returns nil and the empty string if label is not one of the standard encodings for HTML. Matching is case-insensitive and ignores leading and trailing whitespace.

func MentionedAggregateFuncs 

func MentionedAggregateFuncs(e expression.Expression) []expression.Expression

MentionedAggregateFuncs returns a list of the Call expression which is aggregate function.

func MentionedColumns 

func MentionedColumns(e expression.Expression) []string

MentionedColumns returns a list of names for Ident expression.

func NewBetween 

func NewBetween(expr, lo, hi expression.Expression, not bool) (expression.Expression, error)

NewBetween creates a Between expression for "a between c and d" or "a not between c and d". If a doesn't contain any aggregate function, we can split it with logic and comparison expressions. For example: 

a between 10 and 15 -> a >= 10 && a <= 15
a not between 10 and 15 -> a < 10 || b > 15

func NewBinaryOperation 

func NewBinaryOperation(op opcode.Op, x, y expression.Expression) expression.Expression

NewBinaryOperation creates a binary expression with op as the operator code and x, y as the left and right operator expression.

func NewCall 

func NewCall(f string, args []expression.Expression, distinct bool) (v expression.Expression, err error)

NewCall creates a Call expression with function name f, function args arg and a distinct flag whether this function supports distinct or not.

func NewUnaryOperation 

func NewUnaryOperation(op opcode.Op, l expression.Expression) expression.Expression

NewUnaryOperation creates an unary expression.

Types

type Assignment 

type Assignment struct {
	// ColName is the variable name we want to set.
	ColName string
	// Expr is the expression assigning to ColName.
	Expr expression.Expression
}

Assignment is the expression for assignment, like a = 1.

func (*Assignment) String 

func (a *Assignment) String() string

String returns Assignment representation.

type Between 

type Between struct {
	// Expr is the expression to be checked.
	Expr expression.Expression
	// Left is the expression for minimal value in the range.
	Left expression.Expression
	// Right is the expression for maximum value in the range.
	Right expression.Expression
	// Not is true, the expression is "not between and".
	Not bool
}

Between is for "between and" or "not between and" expression.

func (*Between) Clone 

func (b *Between) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*Between) Eval 

func (b *Between) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*Between) IsStatic 

func (b *Between) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*Between) String 

func (b *Between) String() string

String implements the Expression String interface.

type BinaryOperation 

type BinaryOperation struct {
	// Op is the operator code for BinaryOperation.
	Op opcode.Op
	// L is the left expression in BinaryOperation.
	L expression.Expression
	// R is the right expression in BinaryOperation.
	R expression.Expression
}

BinaryOperation is for binary operation like 1 + 1, 1 - 1, etc.

func (*BinaryOperation) Clone 

func (o *BinaryOperation) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*BinaryOperation) Eval 

func (o *BinaryOperation) Eval(ctx context.Context, args map[interface{}]interface{}) (r interface{}, err error)

Eval implements the Expression Eval interface.

func (*BinaryOperation) IsIdentRelOpVal 

func (o *BinaryOperation) IsIdentRelOpVal() (bool, string, interface{}, error)

IsIdentRelOpVal checks left expression is Ident expression and right is Value expression for relational comparison, then returns left identifier name and right value.

func (*BinaryOperation) IsStatic 

func (o *BinaryOperation) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*BinaryOperation) String 

func (o *BinaryOperation) String() string

String implements the Expression String interface.

type Call 

type Call struct {
	// F is the function name.
	F string
	// Args is the function args.
	Args []expression.Expression
	// Distinct only affetcts sum, avg, count, group_concat,
	// so we can ignore it in other functions
	Distinct bool
}

Call is for function expression.

func (*Call) Clone 

func (c *Call) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*Call) Eval 

func (c *Call) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*Call) IsStatic 

func (c *Call) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*Call) String 

func (c *Call) String() string

String implements the Expression String interface.

type Default 

type Default struct {
	// Name is the column name
	Name string
}

Default is the default expression using default value for a column.

func (*Default) Clone 

func (v *Default) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*Default) Eval 

func (v *Default) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*Default) IsStatic 

func (v *Default) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns false.

func (*Default) String 

func (v *Default) String() string

String implements the Expression String interface.

type FunctionCase 

type FunctionCase struct {
	// Value is the compare value expression.
	Value expression.Expression
	// WhenClauses is the condition check expression.
	WhenClauses []*WhenClause
	// ElseClause is the else result expression.
	ElseClause expression.Expression
}

FunctionCase is the case expression.

func (*FunctionCase) Clone 

func (f *FunctionCase) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*FunctionCase) Eval 

func (f *FunctionCase) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*FunctionCase) IsStatic 

func (f *FunctionCase) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*FunctionCase) String 

func (f *FunctionCase) String() string

String implements the Expression String interface.

type FunctionCast 

type FunctionCast struct {
	// Expr is the expression to be converted.
	Expr expression.Expression
	// Tp is the conversion type.
	Tp *types.FieldType
	// Cast and Convert share this struct.
	IsConvert bool
}

FunctionCast is the cast function converting value to another type, e.g, cast(expr AS signed). See https://dev.mysql.com/doc/refman/5.7/en/cast-functions.html#function_cast

func (*FunctionCast) Clone 

func (f *FunctionCast) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*FunctionCast) Eval 

func (f *FunctionCast) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*FunctionCast) IsStatic 

func (f *FunctionCast) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*FunctionCast) String 

func (f *FunctionCast) String() string

String implements the Expression String interface.

type FunctionConvert 

type FunctionConvert struct {
	Expr    expression.Expression
	Charset string
}

FunctionConvert provides a way to convert data between different character sets. See: https://dev.mysql.com/doc/refman/5.7/en/cast-functions.html#function_convert

func (*FunctionConvert) Clone 

func (f *FunctionConvert) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*FunctionConvert) Eval 

func (f *FunctionConvert) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*FunctionConvert) IsStatic 

func (f *FunctionConvert) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*FunctionConvert) String 

func (f *FunctionConvert) String() string

String implements the Expression String interface.

type FunctionSubstring 

type FunctionSubstring struct {
	StrExpr expression.Expression
	Pos     expression.Expression
	Len     expression.Expression
}

FunctionSubstring returns the substring as specified. See: https://dev.mysql.com/doc/refman/5.7/en/string-functions.html#function_substring

func (*FunctionSubstring) Clone 

func (f *FunctionSubstring) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*FunctionSubstring) Eval 

func (f *FunctionSubstring) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*FunctionSubstring) IsStatic 

func (f *FunctionSubstring) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*FunctionSubstring) String 

func (f *FunctionSubstring) String() string

String implements the Expression String interface.

type Ident 

type Ident struct {
	// model.CIStr contains origin identifier name and its lowercase name.
	model.CIStr
}

Ident is the identifier expression.

func (*Ident) Clone 

func (i *Ident) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*Ident) Equal 

func (i *Ident) Equal(x *Ident) bool

Equal checks equation with another Ident expression using lowercase identifier name.

func (*Ident) Eval 

func (i *Ident) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*Ident) IsStatic 

func (i *Ident) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns false.

func (*Ident) String 

func (i *Ident) String() string

String implements the Expression String interface.

type IsNull 

type IsNull struct {
	// Expr is the expression to be checked.
	Expr expression.Expression
	// Not is true, the expression is "is not null".
	Not bool
}

IsNull is the expression for null check.

func (*IsNull) Clone 

func (is *IsNull) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*IsNull) Eval 

func (is *IsNull) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*IsNull) IsStatic 

func (is *IsNull) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*IsNull) String 

func (is *IsNull) String() string

String implements the Expression String interface.

type IsTruth 

type IsTruth struct {
	// Expr is the expression to be checked.
	Expr expression.Expression
	// Not is true, the expression is "is not true/false".
	Not bool
	// True indicates checking true or false.
	True int8
}

IsTruth is the expression for true/false check.

func (*IsTruth) Clone 

func (is *IsTruth) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*IsTruth) Eval 

func (is *IsTruth) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*IsTruth) IsStatic 

func (is *IsTruth) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*IsTruth) String 

func (is *IsTruth) String() string

String implements the Expression String interface.

type PExpr 

type PExpr struct {
	// Expr is the expression in parenthese.
	Expr expression.Expression
}

PExpr is the parenthese expression.

func (*PExpr) Clone 

func (p *PExpr) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*PExpr) Eval 

func (p *PExpr) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*PExpr) IsStatic 

func (p *PExpr) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*PExpr) String 

func (p *PExpr) String() string

String implements the Expression String interface.

type ParamMarker 

type ParamMarker struct {
	// Expr is the expression to be evaluated in this place holder.
	Expr expression.Expression
}

ParamMarker expresion holds a place for another expression. Used in parsing prepare statement.

func (*ParamMarker) Clone 

func (pm *ParamMarker) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*ParamMarker) Eval 

func (pm *ParamMarker) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*ParamMarker) IsStatic 

func (pm *ParamMarker) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns false.

func (*ParamMarker) String 

func (pm *ParamMarker) String() string

String implements the Expression String interface.

type PatternIn 

type PatternIn struct {
	// Expr is the value expression to be compared.
	Expr expression.Expression
	// List is the list expression in compare list.
	List []expression.Expression
	// Not is true, the expression is "not in".
	Not bool
	// Sel is the select statement.
	Sel plan.Planner
}

PatternIn is the expression for in operator, like "expr in (1, 2, 3)" or "expr in (select c from t)".

func (*PatternIn) Clone 

func (n *PatternIn) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*PatternIn) Eval 

func (n *PatternIn) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*PatternIn) IsStatic 

func (n *PatternIn) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*PatternIn) String 

func (n *PatternIn) String() string

String implements the Expression String interface.

type PatternLike 

type PatternLike struct {
	// Expr is the expression to be checked.
	Expr expression.Expression
	// Pattern is the like expression.
	Pattern expression.Expression

	// Not is true, the expression is "not like".
	Not bool
	// contains filtered or unexported fields
}

PatternLike is the expression for like operator, e.g, expr like "%123%"

func (*PatternLike) Clone 

func (p *PatternLike) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*PatternLike) Eval 

func (p *PatternLike) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*PatternLike) IsStatic 

func (p *PatternLike) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*PatternLike) String 

func (p *PatternLike) String() string

String implements the Expression String interface.

type PatternRegexp 

type PatternRegexp struct {
	// Expr is the expression to be checked.
	Expr expression.Expression
	// Pattern is the expression for pattern.
	Pattern expression.Expression
	// Re is the compiled regexp.
	Re *regexp.Regexp
	// Sexpr is the string for Expr expression.
	Sexpr *string
	// Not is true, the expression is "not rlike",
	Not bool
}

PatternRegexp is the pattern expression for pattern match. TODO: refactor later.

func (*PatternRegexp) Clone 

func (p *PatternRegexp) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*PatternRegexp) Eval 

func (p *PatternRegexp) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*PatternRegexp) IsStatic 

func (p *PatternRegexp) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*PatternRegexp) String 

func (p *PatternRegexp) String() string

String implements the Expression String interface.

type Position 

type Position struct {
	// N is the position, started from 1 now.
	N int
	// Name is the corresponding field name if we want better format and explain instead of position.
	Name string
}

Position is the expression for order by and group by position. MySQL use position expression started from 1, it looks a little confused inner. maybe later we will use 0 at first.

func (*Position) Clone 

func (p *Position) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*Position) Eval 

func (p *Position) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*Position) IsStatic 

func (p *Position) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns false.

func (*Position) String 

func (p *Position) String() string

String implements the Expression String interface.

type SubQuery 

type SubQuery struct {
	// Stmt is the sub select statement.
	Stmt stmt.Statement
	// Value holds the sub select result.
	Value interface{}
}

SubQuery expresion holds a select statement. TODO: complete according to https://dev.mysql.com/doc/refman/5.7/en/subquery-restrictions.html

func (*SubQuery) Clone 

func (sq *SubQuery) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*SubQuery) Eval 

func (sq *SubQuery) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface.

func (*SubQuery) IsStatic 

func (sq *SubQuery) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns false.

func (*SubQuery) String 

func (sq *SubQuery) String() string

String implements the Expression String interface.

type TypeStar 

type TypeStar string

TypeStar is the type for *

type UnaryOperation 

type UnaryOperation struct {
	// Op is the operator opcode.
	Op opcode.Op
	// V is the unary expression.
	V expression.Expression
}

UnaryOperation is the expression for unary operator.

func (*UnaryOperation) Clone 

func (u *UnaryOperation) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*UnaryOperation) Eval 

func (u *UnaryOperation) Eval(ctx context.Context, args map[interface{}]interface{}) (r interface{}, err error)

Eval implements the Expression Eval interface.

func (*UnaryOperation) IsStatic 

func (u *UnaryOperation) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*UnaryOperation) String 

func (u *UnaryOperation) String() string

String implements the Expression String interface.

type Value 

type Value struct {
	// Val holds simple value.
	Val interface{}
}

Value is the expression holding simple value.

func (Value) Clone 

func (l Value) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (Value) Eval 

func (l Value) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (Value) IsStatic 

func (l Value) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns true.

func (Value) String 

func (l Value) String() string

String implements the Expression String interface.

type Values 

type Values struct {
	// model.CIStr is column name.
	model.CIStr
}

Values is the expression used in INSERT VALUES

func (*Values) Clone 

func (i *Values) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*Values) Equal 

func (i *Values) Equal(x *Values) bool

Equal check equation with another x Values using lowercase column name.

func (*Values) Eval 

func (i *Values) Eval(ctx context.Context, args map[interface{}]interface{}) (v interface{}, err error)

Eval implements the Expression Eval interface. See: https://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_values

func (*Values) IsStatic 

func (i *Values) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns false.

func (*Values) String 

func (i *Values) String() string

String implements the Expression String interface.

type Variable 

type Variable struct {
	// Name is the variable name.
	Name string
	// IsGlobal indicates whether this variable is global.
	IsGlobal bool
	// IsSystem indicates whether this variable is a global variable in current session.
	IsSystem bool
}

Variable is the expression for variable.

func (*Variable) Clone 

func (v *Variable) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*Variable) Eval 

func (v *Variable) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*Variable) IsStatic 

func (v *Variable) IsStatic() bool

IsStatic implements the Expression IsStatic interface, always returns false.

func (*Variable) String 

func (v *Variable) String() string

String implements the Expression String interface.

type WhenClause 

type WhenClause struct {
	// Expr is the condition expression in WhenClause.
	Expr expression.Expression
	// Result is the result expression in WhenClause.
	Result expression.Expression
}

WhenClause is the expression in Case expression for "when condition then result".

func (*WhenClause) Clone 

func (w *WhenClause) Clone() (expression.Expression, error)

Clone implements the Expression Clone interface.

func (*WhenClause) Eval 

func (w *WhenClause) Eval(ctx context.Context, args map[interface{}]interface{}) (interface{}, error)

Eval implements the Expression Eval interface.

func (*WhenClause) IsStatic 

func (w *WhenClause) IsStatic() bool

IsStatic implements the Expression IsStatic interface.

func (*WhenClause) String 

func (w *WhenClause) String() string

String implements the Expression String interface.

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