Function lag

pub fn lag<'a, V, E>(expr: E) -> WindowFnExpr<'a, V, E::SQLType, Null>where
    V: SQLParam + 'a,
    E: Expr<'a, V>,

Expand description

LAG(expr) — value of expr from the previous row.

Returns the same type as expr, always nullable (no previous row → NULL).

lag