huaxingao commented on a change in pull request #35239:
URL: https://github.com/apache/spark/pull/35239#discussion_r793248260
##########
File path: docs/sql-ref-syntax-ddl-alter-table.md
##########
@@ -75,6 +75,50 @@ ALTER TABLE table_identifier ADD COLUMNS ( col_spec [ , ...
] )
Specifies the columns to be added.
+### DROP COLUMNS
+
+`ALTER TABLE DROP COLUMNS` statement drops mentioned columns from an existing
table.
+Note that this statement is only supported with v2 tables.
+
+
+#### Syntax
+
+```sql
+ALTER TABLE table_identifier DROP COLUMNS ( col_name1, ... )
+```
Review comment:
Here is the syntax:
```
| ALTER TABLE multipartIdentifier
DROP (COLUMN | COLUMNS)
'(' columns=multipartIdentifierList ')'
#dropTableColumns
| ALTER TABLE multipartIdentifier
DROP (COLUMN | COLUMNS) columns=multipartIdentifierList
#dropTableColumns
```
So I think it's something like this:
```
ALTER TABLE table_identifier DROP { COLUMN | COLUMNS } [ ( ] col_name [ ,
... ] [ ) ]
```
I guess add a parameter in the below section for `col_name`.
You might want to change the add column syntax too to make it more accurate.
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