DDL

Data Definition Language: schemas, tables, views, columns, partitions, branches, tags. Most statements parse via sqlparser-rs; SQE adds branch / tag / partition-evolution syntax that sqlparser-rs does not natively understand.

Source: sqe-sql/src/classifier.rs, sqe-sql/src/ddl.rs, sqe-sql/src/partition.rs, sqe-sql/src/partition_evolution.rs. Coordinator handlers in crates/sqe-coordinator/src/catalog_ops.rs.

Schema

Statement	Origin	Notes	Trino	Snowflake	Spark SQL	DuckDB
`CREATE SCHEMA [IF NOT EXISTS] cat.ns`	`sqlparser-rs` + `sqe-coordinator`	Creates a namespace in the catalog.	yes	yes	yes	yes
`CREATE SCHEMA [IF NOT EXISTS] cat.ns LOCATION 's3://...'`	`sqlparser-rs` + `sqe-coordinator`	Override default location. Only on catalogs that accept location at namespace level (Polaris, S3 Tables).	yes	yes	yes	-
`DROP SCHEMA [IF EXISTS] cat.ns [CASCADE\|RESTRICT]`	`sqlparser-rs` + `sqe-coordinator`	`CASCADE` drops contained tables.	yes	yes	yes	yes
`ALTER SCHEMA cat.ns RENAME TO new_name`	`sqlparser-rs` + `sqe-coordinator`	Catalog must support namespace rename.	partial	yes	yes	yes

CREATE SCHEMA IF NOT EXISTS analytics.staging;
CREATE SCHEMA marketing LOCATION 's3://my-warehouse/marketing/';
DROP SCHEMA staging CASCADE;

Table creation

Statement	Origin	Notes	Trino	Snowflake	Spark SQL	DuckDB
`CREATE TABLE t (col TYPE [DEFAULT expr], ...)`	`sqlparser-rs` + `sqe-sql` + `sqe-coordinator`	Iceberg V3 column defaults supported.	yes	yes	yes	yes
`CREATE TABLE t (...) PARTITIONED BY (transform(col), ...)`	`sqe-sql/partition.rs`	Partition transforms: `bucket(N, col)`, `truncate(N, col)`, `year(col)`, `month(col)`, `day(col)`, `hour(col)`, identity (just `col`).	partial	-	yes	-
`CREATE TABLE t AS SELECT ...` (CTAS)	`sqlparser-rs` + `sqe-coordinator`	Inferred schema; partitioning via `WITH (partitioning = ARRAY['day(ts)'])`.	yes	yes	yes	yes
`CREATE OR REPLACE TABLE t AS SELECT ...`	`sqlparser-rs` + `sqe-coordinator`	Atomic replace. New snapshot replaces the table; old data files retained until `expire_snapshots`.	yes	yes	partial	yes
`CREATE TABLE [IF NOT EXISTS] t LIKE other_table`	`sqlparser-rs` + `sqe-coordinator`	Copy schema only, no data.	yes	yes	yes	yes

CREATE TABLE analytics.events (
    id          BIGINT,
    user_id     BIGINT,
    event_type  VARCHAR,
    occurred_at TIMESTAMP(6),
    payload     JSON,
    region      VARCHAR DEFAULT 'unknown'
)
PARTITIONED BY (day(occurred_at), bucket(16, user_id));

CREATE TABLE analytics.daily_events AS
SELECT day(occurred_at) AS d, count(*) AS n
FROM analytics.events GROUP BY 1;

Schema evolution

Statement	Origin	Notes	Trino	Snowflake	Spark SQL	DuckDB
`ALTER TABLE t ADD COLUMN c TYPE [DEFAULT expr]`	`sqlparser-rs` + `sqe-coordinator`	New column. Existing rows get the default (V3) or NULL (V2).	yes	yes	yes	yes
`ALTER TABLE t DROP COLUMN [IF EXISTS] c`	`sqlparser-rs` + `sqe-coordinator`	Logical drop. Field id retained in old data files.	yes	yes	yes	yes
`ALTER TABLE t RENAME COLUMN old TO new`	`sqlparser-rs` + `sqe-coordinator`	Iceberg field id stays the same; only the name changes.	yes	yes	yes	yes
`ALTER TABLE t ALTER COLUMN c SET NOT NULL`	`sqlparser-rs` + `sqe-coordinator`	Tighten nullability. Fails if existing rows have NULL.	yes	yes	yes	yes
`ALTER TABLE t ALTER COLUMN c DROP NOT NULL`	`sqlparser-rs` + `sqe-coordinator`	Loosen nullability.	yes	yes	yes	yes
`ALTER TABLE t ALTER COLUMN c SET DEFAULT expr`	`sqlparser-rs` + `sqe-coordinator`	Iceberg V3 column default.	partial	yes	yes	yes
`ALTER TABLE t ALTER COLUMN c TYPE new_type`	`sqlparser-rs` + `sqe-coordinator`	Type promotion only (e.g. INT -> BIGINT). Lossy changes rejected.	partial	partial	partial	partial
`ALTER TABLE t RENAME TO new_t`	`sqlparser-rs` + `sqe-coordinator`	Catalog rename. Different catalog support varies.	yes	yes	yes	yes
`ALTER TABLE t SET TBLPROPERTIES (...)`	`sqlparser-rs` + `sqe-coordinator`	Set Iceberg properties (e.g. `write.delete.mode`).	yes	yes	yes	-
`COMMENT ON TABLE t IS 'description'`	`sqlparser-rs` + `sqe-coordinator`	Stored in Iceberg properties.	yes	yes	yes	yes
`COMMENT ON COLUMN t.c IS 'description'`	`sqlparser-rs` + `sqe-coordinator`	Stored on the column metadata.	yes	yes	yes	yes

ALTER TABLE analytics.events ADD COLUMN device VARCHAR DEFAULT 'unknown';
ALTER TABLE analytics.events DROP COLUMN IF EXISTS deprecated_field;
ALTER TABLE analytics.events RENAME COLUMN payload TO body;
ALTER TABLE analytics.events ALTER COLUMN region SET NOT NULL;
ALTER TABLE analytics.events SET TBLPROPERTIES (
    'write.delete.mode' = 'merge-on-read',
    'write.parquet.bloom-filter-columns' = 'user_id,event_id'
);

Partition evolution (SQE / Iceberg-specific)

Iceberg lets you change partition spec without rewriting data. SQE parses these in sqe-sql/src/partition_evolution.rs because sqlparser-rs only knows Hive-style PARTITION (col = val).

Statement	Notes	Trino	Snowflake	Spark SQL
`ALTER TABLE t ADD PARTITION FIELD transform(col)`	Add a new partition field. Existing data stays in the old spec.	partial	-	yes
`ALTER TABLE t ADD PARTITION FIELD transform(col) AS alias`	Same with explicit name for the partition column.	-	-	yes
`ALTER TABLE t DROP PARTITION FIELD transform(col)`	Remove a partition field from the current spec.	partial	-	yes
`ALTER TABLE t REPLACE PARTITION FIELD old_transform(col) WITH new_transform(col)`	Replace one transform with another.	-	-	yes

-- Originally partitioned by day(ts); switch to hour() for finer granularity.
ALTER TABLE events REPLACE PARTITION FIELD day(occurred_at) WITH hour(occurred_at);

-- Add a bucketing field on top of existing daily partitions.
ALTER TABLE events ADD PARTITION FIELD bucket(64, user_id);

Branches and tags (SQE / Iceberg-specific)

Iceberg branches are named pointers to a snapshot, like git branches. Tags are immutable named pointers. SQE parses these in sqe-sql/src/ddl.rs.

Statement	Notes
`ALTER TABLE t CREATE BRANCH name`	New branch from current snapshot.
`ALTER TABLE t CREATE BRANCH name AS OF VERSION snapshot_id`	New branch from a specific snapshot.
`ALTER TABLE t CREATE BRANCH name WITH RETENTION (max_ref_age_ms = N)`	Auto-expire branch after N ms of inactivity.
`ALTER TABLE t CREATE [OR REPLACE] TAG name`	New tag pointing at current snapshot. `OR REPLACE` is allowed because tags are not strictly immutable in iceberg-rust.
`ALTER TABLE t CREATE TAG name AS OF VERSION snapshot_id`	Tag a specific snapshot.
`ALTER TABLE t DROP BRANCH [IF EXISTS] name`	Remove a branch.
`ALTER TABLE t DROP TAG [IF EXISTS] name`	Remove a tag.

-- Branch a snapshot for development work
ALTER TABLE analytics.events CREATE BRANCH dev_2026_05;

-- Pin a known-good snapshot as a tag
ALTER TABLE analytics.events CREATE TAG release_2026_q2 AS OF VERSION 8472810294;

-- Query the branch
SELECT * FROM analytics.events FOR VERSION AS OF 'dev_2026_05';

Views

Statement	Origin	Notes	Trino	Snowflake	Spark SQL	DuckDB
`CREATE [OR REPLACE] VIEW v AS SELECT ...`	`sqlparser-rs` + `sqe-coordinator`	Standard SQL view. Iceberg views format-version 1.	yes	yes	yes	yes
`CREATE [OR REPLACE] VIEW v (col1, col2) AS SELECT ...`	`sqlparser-rs` + `sqe-coordinator`	Explicit column list.	yes	yes	yes	yes
`DROP VIEW [IF EXISTS] v`	`sqlparser-rs` + `sqe-coordinator`	Remove a view.	yes	yes	yes	yes

CREATE OR REPLACE VIEW analytics.recent_events AS
SELECT * FROM analytics.events
WHERE occurred_at >= now() - INTERVAL '7' DAY;

DROP VIEW IF EXISTS analytics.recent_events;

Drop

Statement	Origin	Notes
`DROP TABLE [IF EXISTS] t [PURGE]`	`sqlparser-rs` + `sqe-coordinator`	`PURGE` deletes data files immediately; default keeps the metadata so `system.remove_orphan_files` can clean later.
`DROP VIEW [IF EXISTS] v`	`sqlparser-rs` + `sqe-coordinator`	Standard.
`DROP SCHEMA [IF EXISTS] s [CASCADE\|RESTRICT]`	`sqlparser-rs` + `sqe-coordinator`	`CASCADE` drops contained tables.

Iceberg V3 type system

These types only exist in format-version 3. Adding one to a CREATE TABLE auto-bumps the table to V3.

Type	Notes
`TIMESTAMP_NS`, `TIMESTAMP_NS WITH TIME ZONE`	Nanosecond precision timestamps. Arrow `Timestamp(Nanosecond, ...)`.
`GEOMETRY`, `GEOGRAPHY`	Stub types in V3; SQE accepts them in CREATE but does not yet provide spatial functions.
Default values via `DEFAULT expr`	Existing rows in older snapshots inherit the default at read time.

What CREATE / ALTER does NOT cover

CREATE INDEX. Iceberg has no equivalent. Bloom filter columns and partition fields cover the same ground; configure via SET TBLPROPERTIES and ADD PARTITION FIELD.
CREATE FUNCTION / CREATE PROCEDURE. UDFs are Rust-side. SQL-defined functions and procedures are not supported.
CREATE SEQUENCE. no auto-increment / sequence support today. Use row_number() over a deterministic ordering for synthetic keys.
CREATE TYPE. no user-defined types. Use STRUCT<...> or MAP<...>.

These are tracked but not on the immediate roadmap.

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