SQL_DIALECT.md

SQL dialect

This document describes the supported subset of SQL (the project’s dialect) and limitations.

General rules

• String literals: single quotes '...'.
• Identifiers: Latin letters/digits/_ (see the lexer for details).
• Semicolons ; are allowed and recommended in interactive mode.

Data types

Currently supported:

• INT64 — 64-bit integer
• VARCHAR — variable-length string

CREATE TABLE

Syntax:

CREATE TABLE table_name (
  col1 TYPE,
  col2 TYPE,
  ...
);

Example:

CREATE TABLE users (id INT64, name VARCHAR, age INT64);

INSERT

Syntax:

INSERT INTO table_name VALUES (value1, value2, ...);

Example:

INSERT INTO users VALUES (1, 'Alice', 25);

SELECT

Syntax:

SELECT targets FROM table_name [WHERE predicate];

Supported:

• * (all columns)
• a list of expressions: col, col1 + col2, price * 2
• aliases: expr AS alias
• WHERE predicates with AND/OR
• comparisons: =, !=, <, >, <=, >=

Examples:

SELECT * FROM users;
SELECT id, name FROM users WHERE id > 10 AND age <= 30;
SELECT name, age + 1 AS next_age FROM users WHERE name != 'Bob';

CREATE INDEX

Syntax:

CREATE INDEX index_name ON table_name(column_name) USING type;

Where type is:

• HASH — for point lookups (predicate =)
• BTREE — for ranges (<, <=, >, >=) and point lookups (see INDEXES.md)

Example:

CREATE INDEX idx_users_id ON users(id) USING HASH;

Limitations

Not supported in the current version:

• UPDATE, DELETE
• DROP TABLE, DROP INDEX
• JOIN, GROUP BY, ORDER BY, LIMIT
• transactions and a full concurrency model

See ROADMAP.md for the up-to-date plan.