# Presto 316 Documentation

## 7.4. Lambda Expressions

Lambda expressions are written with `->`:

    x -> x + 1
    (x, y) -> x + y
    x -> regexp_like(x, 'a+')
    x -> x[1] / x[2]
    x -> IF(x > 0, x, -x)
    x -> COALESCE(x, 0)
    x -> CAST(x AS JSON)
    x -> x + TRY(1 / 0)

Most SQL expressions can be used in a lambda body, with a few exceptions:

- Subqueries are not supported. `x -> 2 + (SELECT 3)`
- Aggregations are not supported. `x -> max(y)`