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MODIFY ÏÂÁîÔÚ SQL ÖÐÓÃÓÚÐ޸ıí½á¹¹£¬ÏêϸÀ´Ëµ£¬Ëü¿ÉÒÔÓÃÓÚ£º

1. Ìí¼ÓÁÐ

ALTER TABLE table_name ADD COLUMN new_column_name data_type;

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2. ɾ³ýÁÐ

ALTER TABLE table_name DROP COLUMN column_name;

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3. ÐÞ¸ÄÁÐÊý¾ÝÀàÐÍ

ALTER TABLE table_name ALTER COLUMN column_name SET DATA TYPE new_data_type;

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4. ÐÞ¸ÄÁÐĬÈÏÖµ

ALTER TABLE table_name ALTER COLUMN column_name SET DEFAULT default_value;

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5. ÐÞ¸ÄÁÐÄÜ·ñΪ¿Õ

ALTER TABLE table_name ALTER COLUMN column_name SET NOT NULL;
ALTER TABLE table_name ALTER COLUMN column_name SET NULL;

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data_type ÊÇÐÂÌí¼ÓÁлòÐÞ¸ÄÁеÄÊý¾ÝÀàÐÍ¡£

default_value ÊÇÐÂÌí¼ÓÁлòÐÞ¸ÄÁеÄĬÈÏÖµ¡£

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