Lexical syntax

Keywords, identifiers, literals, comments, parameters, INTERVAL literals and the one-statement, 64 KiB request boundary.

These are the lexical rules of NYXDB SQL.

Keywords

Keywords are case-insensitive: select, SELECT and Select are the same keyword. The pages of this reference write them in upper case.

Identifiers

An identifier names a table, column, index, attribute group, view or transformation.

It starts with an ASCII letter or _ and continues with ASCII letters, digits and _.
It is at most 128 bytes.
It is case-insensitive and stored in lower case: a table created as Balances is the table balances. Prefer snake_case names.
Double quotes delimit an identifier that contains spaces or punctuation.
A system relation is named with a dot, such as system.tables, and a column can be qualified by its relation alias, such as t.token.

Literals

Literal	Form
string	single quotes; a quote inside is written twice, so `'it''s'` is `it's`
number	decimal digits with an optional fractional part, such as `42` or `-12.50`; no exponent and no hexadecimal form
Boolean	`TRUE`, `FALSE`
null	`NULL`

Typed values such as dates, timestamps and UUIDs are written as string literals and converted to the column's type. The accepted spellings are on Data types and INSERT.

Comments

-- starts a comment that runs to the end of the line (a line feed or a carriage return).
/* … */ is a block comment. Block comments do not nest: the first */ closes the comment. The error for an unterminated block comment gives the byte offset where it starts.
Comment markers inside a string literal are text, not comments.

A statement holds at least one token besides comments.

An unquoted ? in a statement is a positional parameter. Its value is sent with the request, in parameter order, and is bound to the type of the column it is compared with. A ? inside a string literal is text. See Protocol for how parameter values are carried, and SELECT for an example.

Named parameters of the form ${name:TYPE} belong to parameterized views and materialized views; see Views.

INTERVAL literals

INTERVAL <n> <unit> is a duration: n is a positive integer without a sign or a fractional part, and the unit is one of MICROSECOND, MILLISECOND, SECOND, MINUTE, HOUR or DAY, in the singular or with a trailing S (INTERVAL 5 MINUTES). Intervals appear in window relations and EMIT clauses of streaming queries and as values of the SETTINGS clause.

One statement per request

A request carries one statement, with an optional trailing ;. The statement text, comments included, is up to 64 KiB.

Statements are sent over HTTP POST /sql or as frames of a WebSocket session; see Protocol. Session statements such as SET and the federation statements run on a WebSocket session.