typesql types#

typesql mirrors the lake's physical kinds and adds expression-only composite types. A type describes a value; it never changes that value.

Scalar types#

Type	Meaning
`boolean`	`true` or `false`
`integer`	Signed 64-bit integer
`decimal(p, s)`	Exact decimal, up to precision 38
`float`	64-bit floating-point value
`date`	Calendar date
`datetime`	Timestamp without an offset, stored at microsecond precision
`datetimetz`	Instant, stored at microsecond precision
`string`	UTF-8 text
`json`	JSON without a declared shape
`binary`	Binary value carried as canonical base64 text

unknown means the checker has insufficient evidence. never represents a path that cannot produce a value.

Nullability#

Lake values are nullable unless the catalog supplies current proof otherwise. A trailing ! requires a non-null value:

typesql

select id satisfies string!
from titan.stripe.customers
where id is not null

Predicates such as is not null narrow values in their valid flow scope. A cast does not prove that its result is non-null.

Composite types#

Expression-time collections use list<T>, struct{field: T}, and map<K, V>. Table shapes name ordered columns:

typesql

with customer_totals(customer_id: string!, revenue: decimal(18, 2)) as (
  select customer, sum(amount) / 100.0
  from titan.stripe.charges
  group by customer
)
select * from customer_totals

Shaped JSON#

json<{...}> describes fields available inside a JSON carrier while preserving its runtime representation:

typesql

select metadata satisfies json<{campaign: string, cohort: string}>
from titan.stripe.customers

Connector-shape packages can provide these shapes by name so every query does not repeat them.

Masked types#

masked<T> records column-policy provenance. It cannot be cast away, compared as an ordinary value, or merged with an unmasked branch. Failures use TS0410 for casts, TS0411 for comparisons, and TS0412 for unsafe flow. Compatible projections and union all preserve the wrapper.