Enum models_parser::ast::Expr [−][src]
pub enum Expr {
Show 26 variants
Identifier(Ident),
Wildcard,
QualifiedWildcard(Vec<Ident>),
CompoundIdentifier(Vec<Ident>),
IsNull(Box<Expr>),
IsNotNull(Box<Expr>),
InList(InList),
InSubquery(InSubquery),
Between(Between),
BinaryOp(BinaryOp),
UnaryOp(UnaryOp),
Cast(Cast),
TryCast(TryCast),
Extract(Extract),
Substring(Substring),
Trim(Trim),
Collate(Collate),
Nested(Box<Expr>),
Value(Value),
TypedString(TypedString),
MapAccess(MapAccess),
Function(Function),
Case(Case),
Exists(Box<Query>),
Subquery(Box<Query>),
ListAgg(ListAgg),
}
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
Tuple Fields of Identifier
0: Ident
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
InList(InList)
[ NOT ] IN (val1, val2, ...)
Tuple Fields of InList
0: InList
InSubquery(InSubquery)
[ NOT ] IN (SELECT ...)
Tuple Fields of InSubquery
0: InSubquery
Between(Between)
<expr> [ NOT ] BETWEEN <low> AND <high>
Tuple Fields of Between
0: Between
BinaryOp(BinaryOp)
Binary operation e.g. 1 + 1
or foo > bar
Tuple Fields of BinaryOp
0: BinaryOp
UnaryOp(UnaryOp)
Unary operation e.g. NOT foo
Tuple Fields of UnaryOp
0: UnaryOp
Cast(Cast)
CAST an expression to a different data type e.g. CAST(foo AS VARCHAR(123))
Tuple Fields of Cast
0: Cast
TryCast(TryCast)
TRY_CAST an expression to a different data type e.g. TRY_CAST(foo AS VARCHAR(123))
Tuple Fields of TryCast
0: TryCast
Extract(Extract)
EXTRACT(DateTimeField FROM
Tuple Fields of Extract
0: Extract
Substring(Substring)
SUBSTRING(
Tuple Fields of Substring
0: Substring
Trim(Trim)
TRIM([BOTH | LEADING | TRAILING]
Or
TRIM(
Tuple Fields of Trim
0: Trim
Collate(Collate)
expr COLLATE collation
Tuple Fields of Collate
0: Collate
Nested expression e.g. (foo > bar)
or (1)
Value(Value)
A literal value, such as string, number, date or NULL
Tuple Fields of Value
0: Value
TypedString(TypedString)
A constant of form <data_type> 'value'
.
This can represent ANSI SQL DATE
, TIME
, and TIMESTAMP
literals (such as DATE '2020-01-01'
),
as well as constants of other types (a non-standard PostgreSQL extension).
Tuple Fields of TypedString
0: TypedString
MapAccess(MapAccess)
Tuple Fields of MapAccess
0: MapAccess
Function(Function)
Scalar function call e.g. LEFT(foo, 5)
Tuple Fields of Function
0: Function
Case(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
Tuple Fields of Case
0: Case
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
ListAgg(ListAgg)
The LISTAGG
function SELECT LISTAGG(...) WITHIN GROUP (ORDER BY ...)
Tuple Fields of ListAgg
0: ListAgg
Trait Implementations
Auto Trait Implementations
impl RefUnwindSafe for Expr
impl UnwindSafe for Expr
Blanket Implementations
Mutably borrows from an owned value. Read more