[youdie006]

#338 stopped COMMENT, CODEC and TTL from being read as a type name when a column's type is omitted. The same guard in parseTableColumnExpr doesn't skip DEFAULT, MATERIALIZED and ALIAS, which are handled a few lines below it, so a column that omits its type before one of them either fails to parse or is misparsed. ClickHouse allows this: "The column type of a default value column can be omitted in which case it is inferred from expr's type", e.g. EventDate DEFAULT toDate(EventTime) (CREATE TABLE, default values).

CREATE TABLE t (ts DateTime, d DEFAULT ts + 1) ENGINE = MergeTree ORDER BY ts
  before: line 1:40 expected ')', but got '<ident>'
  after:  column d: Type="" DefaultExpr="ts + 1"
ALTER TABLE t MODIFY COLUMN m MATERIALIZED toDate(ts)
  before: line 1:44 <EOF> or ';' was expected, but got: "toDate"
  after:  column m: Type="" MaterializedExpr="toDate(ts)"
ALTER TABLE t ADD COLUMN a ALIAS ts
  before: line 1:34 <EOF> or ';' was expected, but got: "ts"
  after:  column a: Type="" AliasExpr="ts"
ALTER TABLE t MODIFY COLUMN d DEFAULT (1)
  before: column d: Type="DEFAULT(1)" DefaultExpr=""
  after:  column d: Type="" DefaultExpr="(1)"

This adds the three keywords to that guard. All three statements (CREATE, ADD COLUMN, MODIFY COLUMN) go through parseTableColumnExpr. TestParser_ColumnValueExprWithoutType covers each keyword in each statement, including Date DEFAULT today() and Nullable(String) ALIAS 'x', where the type must still be parsed. It also checks that DEFAULT, MATERIALIZED or ALIAS without an expression is an error; those used to parse as a type name, and the docs say a type is required when the expression is left out. New fixture parser/testdata/ddl/column_value_without_type.sql, with goldens regenerated by -update; no other golden changed.

clickhouse-local was not available here, so the syntax is checked against the docs above rather than the engine. go test -v ./... -covermode=atomic -race -compatible (as make test) passes and gofmt is clean; I couldn't run make lint, since golangci-lint v1.53.3 isn't installed.

Written with AI assistance (Claude); I have reviewed the change.

[git-hulk]

@youdie006 Thanks for your improvement.