Enum sql_ast::ast::Expr [−][src]
pub enum Expr {}Show variants
Identifier(Ident), Wildcard, QualifiedWildcard(Vec<Ident>), CompoundIdentifier(Vec<Ident>), IsNull(Box<Expr>), IsNotNull(Box<Expr>), InList { expr: Box<Expr>, list: Vec<Expr>, negated: bool, }, ValueList(Vec<Expr>), 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>),
Expand description
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
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 * + *
Qualified wildcard, e.g. alias.*
or schema.table.*
.
(Same caveats apply to QualifiedWildcard
as to Wildcard
.)
Multi-part identifier, e.g. table_alias.column
or schema.table.col
IS NULL
expression
IS NOT NULL
expression
[ NOT ] IN (val1, val2, ...)
[ NOT ] IN (SELECT ...)
<expr> [ NOT ] BETWEEN <low> AND <high>
Binary operation e.g. 1 + 1
or foo > bar
Show fields
Fields of BinaryOp
Unary operation e.g. NOT foo
Show fields
Fields of UnaryOp
op: UnaryOperator
expr: Box<Expr>
CAST an expression to a different data type e.g. CAST(foo AS VARCHAR(123))
Show fields
Fields of Extract
field: DateTimeField
expr: Box<Expr>
expr COLLATE collation
Show fields
Fields of Collate
expr: Box<Expr>
collation: ObjectName
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 [<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
Show fields
An exists expression EXISTS(SELECT ...)
, used in expressions like
WHERE EXISTS (SELECT ...)
.
A parenthesized subquery (SELECT ...)
, used in expression like
SELECT (subquery) AS x
or WHERE (subquery) = x
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for Expr
impl UnwindSafe for Expr
Blanket Implementations
Mutably borrows from an owned value. Read more