Struct Compound 

pub struct Compound {
    pub op: Option<CompoundOp>,
    pub query: Option<Expr>,
}

One operand of a compound SELECT: UNION ALL <select-core>.

The operand is not parenthesised, and that is the whole reason this type exists instead of Combine. SQLite’s compound-select-stmt is a sequence of bare select-cores:

select-core ( compound-operator select-core )*

A parenthesised select is only a table-or-subquery in SQLite, never a compound operand, so (SELECT 1) UNION (SELECT 2) is a syntax error — verified against SQLite’s own parser and against a real SQLite. PostgreSQL parenthesises every operand so that one may carry its own ORDER BY/LIMIT; SQLite cannot express that at all, and correspondingly has no need for the _combined mods keelson_psql carries.

Fields

op: Option<CompoundOp>

Which operator. None is how a default-constructed operand stays absent.

query: Option<Expr>

The operand, rendered bare.

Implementations

impl Compound

pub fn new(op: CompoundOp, query: impl IntoExpr) -> Compound

A compound operand joined by op.

pub fn is_empty(&self) -> bool

Whether this operand is absent.

Trait Implementations

impl Clone for Compound

fn clone(&self) -> Compound

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Compound

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

Formats the value using the given formatter.

impl Default for Compound

fn default() -> Compound

Returns the “default value” for a type.

impl Expression for Compound

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

Append this fragment to w.