Enum sql_ast::ast::Expr

pub enum Expr {
    Identifier(Ident),
    Wildcard,
    QualifiedWildcard(Vec<Ident>),
    CompoundIdentifier(Vec<Ident>),
    IsNull(Box<Expr>),
    IsNotNull(Box<Expr>),
    InList {
        expr: Box<Expr>,
        list: Vec<Expr>,
        negated: bool,
    },
    InSubquery {
        expr: Box<Expr>,
        subquery: Box<Query>,
        negated: bool,
    },
    Between {
        expr: Box<Expr>,
        negated: bool,
        low: Box<Expr>,
        high: Box<Expr>,
    },
    BinaryOp {
        left: Box<Expr>,
        op: BinaryOperator,
        right: Box<Expr>,
    },
    UnaryOp {
        op: UnaryOperator,
        expr: Box<Expr>,
    },
    Cast {
        expr: Box<Expr>,
        data_type: DataType,
    },
    Extract {
        field: DateTimeField,
        expr: Box<Expr>,
    },
    Collate {
        expr: Box<Expr>,
        collation: ObjectName,
    },
    Nested(Box<Expr>),
    Value(Value),
    Function(Function),
    Case {
        operand: Option<Box<Expr>>,
        conditions: Vec<Expr>,
        results: Vec<Expr>,
        else_result: Option<Box<Expr>>,
    },
    Exists(Box<Query>),
    Subquery(Box<Query>),
}

An SQL expression of any type.

The parser does not distinguish between expressions of different types (e.g. boolean vs string), so the caller must handle expressions of inappropriate type, like WHERE 1 or SELECT 1=1, as necessary.

Variants

Identifier(Ident)

Identifier e.g. table name or column name

Wildcard

Unqualified wildcard (*). SQL allows this in limited contexts, such as:

• right after SELECT (which is represented as a SelectItem::Wildcard instead)
• or as part of an aggregate function, e.g. COUNT(*),

...but we currently also accept it in contexts where it doesn't make sense, such as * + *

QualifiedWildcard(Vec<Ident>)

Qualified wildcard, e.g. alias.* or schema.table.*. (Same caveats apply to QualifiedWildcard as to Wildcard.)

CompoundIdentifier(Vec<Ident>)

Multi-part identifier, e.g. table_alias.column or schema.table.col

IsNull(Box<Expr>)

IS NULL expression

IsNotNull(Box<Expr>)

IS NOT NULL expression

InList

[ NOT ] IN (val1, val2, ...)

Fields of InList

expr: Box<Expr>list: Vec<Expr>negated: bool

InSubquery

[ NOT ] IN (SELECT ...)

Fields of InSubquery

expr: Box<Expr>subquery: Box<Query>negated: bool

Between

<expr> [ NOT ] BETWEEN <low> AND <high>

Fields of Between

expr: Box<Expr>negated: boollow: Box<Expr>high: Box<Expr>

BinaryOp

Binary operation e.g. 1 + 1 or foo > bar

Fields of BinaryOp

left: Box<Expr>op: BinaryOperatorright: Box<Expr>

UnaryOp

Unary operation e.g. NOT foo

Fields of UnaryOp

op: UnaryOperatorexpr: Box<Expr>

Cast

CAST an expression to a different data type e.g. CAST(foo AS VARCHAR(123))

Fields of Cast

expr: Box<Expr>data_type: DataType

Extract

Fields of Extract

field: DateTimeFieldexpr: Box<Expr>

Collate

expr COLLATE collation

Fields of Collate

expr: Box<Expr>collation: ObjectName

Nested(Box<Expr>)

Nested expression e.g. (foo > bar) or (1)

Value(Value)

A literal value, such as string, number, date or NULL

Function(Function)

Scalar function call e.g. LEFT(foo, 5)

Case

CASE [<operand>] WHEN <condition> THEN <result> ... [ELSE <result>] END

Note we only recognize a complete single expression as <condition>, not < 0 nor 1, 2, 3 as allowed in a <simple when clause> per https://jakewheat.github.io/sql-overview/sql-2011-foundation-grammar.html#simple-when-clause

Fields of Case

operand: Option<Box<Expr>>conditions: Vec<Expr>results: Vec<Expr>else_result: Option<Box<Expr>>

Exists(Box<Query>)

An exists expression EXISTS(SELECT ...), used in expressions like WHERE EXISTS (SELECT ...).

Subquery(Box<Query>)

A parenthesized subquery (SELECT ...), used in expression like SELECT (subquery) AS x or WHERE (subquery) = x

Trait Implementations

impl Clone for Expr

fn clone(&self) -> Expr

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Expr

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Display for Expr

fn fmt(&self, f: &mut Formatter) -> Result

Formats the value using the given formatter.

impl Eq for Expr

impl Hash for Expr

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given [Hasher].

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given [Hasher].

impl PartialEq<Expr> for Expr

fn eq(&self, other: &Expr) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Expr) -> bool

This method tests for !=.

impl StructuralEq for Expr

impl StructuralPartialEq for Expr