Struct Combine 

pub struct Combine {
    pub op: Option<SetOp>,
    pub query: Option<Expr>,
    pub all: bool,
}

UNION [ALL] (<query>)

The operand is always parenthesised. It does not have to be — a UNION b UNION c is legal and left-associative — but a parenthesised operand cannot be re-associated by a later ORDER BY, and it is the only way an operand that has its own LIMIT can be written at all.

Fields

op: Option<SetOp>

Which set operation. None is how a default-constructed Combine stays absent.

query: Option<Expr>

The right-hand operand, rendered inside parentheses.

all: bool

ALL: keep duplicate rows instead of removing them.

Implementations

impl Combine

pub fn new(op: SetOp, query: impl IntoExpr) -> Self

A set operation of op against query, without ALL.

pub fn is_empty(&self) -> bool

Whether this operation is absent.

Trait Implementations

impl Clone for Combine

fn clone(&self) -> Combine

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Combine

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

Formats the value using the given formatter.

impl Default for Combine

fn default() -> Combine

Returns the “default value” for a type.

impl Expression for Combine

fn write_sql(&self, w: &mut SqlWriter<'_>)

Append this fragment to w.