[princejain756]

Summary

ALTER TABLE t ADD a int, b int parsed only the first column. Everything after the first comma fell into a single AlterOperation.UNSPECIFIC expression holding raw re-spaced text, so tools walking getColDataTypeList() saw just a int (#2837, also reported as a parse error back in #1651).

T-SQL and Snowflake let one ADD list several column definitions and table constraints without repeating ADD. The ADD branch of AlterExpressionAddAlterModify now loops on comma-separated items under the SQLSERVER and SNOWFLAKE dialects. Each item is either a column definition or, when it starts with CONSTRAINT/CHECK/PRIMARY/UNIQUE/FOREIGN, a TableConstraint. A new semantic lookahead (isAlterAddListItemAhead) keeps the loop from claiming commas that start a separate alter action, and the dialect gate leaves every other grammar path unchanged.

Deparsing needed one model flag: AlterExpression unconditionally wrapped multi-column lists in brackets, which T-SQL does not accept, and dropped a constraint when columns were present. The new bareAddList flag, set only when this list form is parsed, keeps the output unbracketed and emits a trailing constraint after the column list. Programmatically built expressions keep the existing bracketed output.

Test plan

• ALTER TABLE t ADD a int, b varchar(10) NOT NULL, c int under SQLSERVER parses as one ADD with colDataTypeList of 3 and round-trips
• ALTER TABLE t ADD a int, CONSTRAINT ck CHECK (a > 0) under SQLSERVER attaches a real constraint, not UNSPECIFIC text
• ALTER TABLE t ADD COLUMN a int, b int under SNOWFLAKE parses both columns
• Regression tests in AlterTest; full suite 10,738 tests, 0 failures

[manticore-projects]

Looks good, but can you please fix the Codazy exceptions regarding test method names.

[princejain756]

Renamed the new test methods to camelCase in 5e2cb05 - Codacy is green now.

[manticore-projects]

Thank you much!