database - 我应该如何在 redshift 数据库中删除多个列？

Question

你好，我正在尝试从我的表中删除列，特别是在 Amazon Redshift 数据库中，我已经尝试过“Alter Table ABC drop column C1,drop column C2”和“Alter Table ABC drop column C1,C2)”但它显示错误并且没有执行

Answer 1

来自 Redshift's ALTER TABLE documentation ，您不能一次删除多个列，cf:

ALTER TABLE table_name
{
ADD table_constraint |
DROP CONSTRAINT constraint_name [ RESTRICT | CASCADE ] |
OWNER TO new_owner |
RENAME TO new_name |
RENAME COLUMN column_name TO new_name |
ADD [ COLUMN ] column_name column_type
[ DEFAULT default_expr ]
[ ENCODE encoding ]
[ NOT NULL | NULL ] |
DROP [ COLUMN ] column_name [ RESTRICT | CASCADE ] }

where table_constraint is:

[ CONSTRAINT constraint_name ]
{ UNIQUE ( column_name [, ... ] )  |
PRIMARY KEY ( column_name [, ... ] ) |
FOREIGN KEY (column_name [, ... ] )
REFERENCES  reftable [ ( refcolumn ) ]}

因此，我建议您按以下方式进行:

ALTER TABLE ABC DROP COLUMN C1;
ALTER TABLE ABC DROP COLUMN C2;