要修改字段的注释,需要使用ALTER TABLE语句的CHANGE子句,语法如下: ALTERTABLEtable_name CHANGECOLUMNcolumn_name column_name data_type[NULL|NOTNULL][DEFAULTvalue][COMMENT'new_comment']; 1. 2. 其中,table_name是要修改的表名,column_name是要修改的字段名,data_type是字段的数据类型,NULL或NOT NULL表示字段...
1）change mysql> alter table t1 change number id char(2);Query OK, 0 rows affected (0.08 sec)Records: 0 Duplicates: 0 Warnings: 0 2）modify mysql> alter table t1 modify id num int(2);ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that...
For complete tips on Oracle alter table syntax, see the book "Easy Oracle Jumpstart". Oracle provides "alter table" syntax to modify data columns in-place in this form: alter table table_name modify column_name datatype; If you are brave you can use a single "alter table" syntax to mod...
The proposed syntax is : ALTER TABLE ... RENAME COLUMN old_name TO new_name; This worklog will do the parser changes and implement the syntax changes. The new proposed syntax is expected to behave the same as "ALTER TABLE ... CHANGE" command used to rename column, without changing ...
ALTERTABLEtable_nameALTERCOLUMNcolumn_nameSETDEFAULTdefault_expression 在外部資料表中,您只能執行ALTER TABLE SET OWNER和ALTER TABLE RENAME TO。 所需的權限 如果您使用 Unity Catalog ,則必須具有以下項目的MODIFY權限: ALTER COLUMN ADD COLUMN DROP COLUMN ...
syntaxsql Copy ALTER TABLE { database_name.schema_name.table_name | schema_name.table_name | table_name } { ALTER COLUMN column_name { [ type_schema_name. ] type_name [ ( { precision [ , scale ] | max | xml_schema_collection } ) ] [ COLLATE collation_name ] [ NULL | NOT ...
ALTER TABLE - ALTER/MODIFY DATATYPE To change the data type of a column in a table, use the following syntax: SQL Server / MS Access: ALTERTABLEtable_name ALTERCOLUMNcolumn_name datatype; My SQL / Oracle (prior version 10G): ALTERTABLEtable_name ...
table_name modify column_name datatype; If you are brave you can use a single "alter table" syntax to modify multiple columns: alter table table_name modify ( column1_name column1_datatype, column2_name column2_datatype, column3_name column3_datatype, ...
Groups of ALTER TABLE syntax: alter_table_properties::= column_clauses::= constraint_clauses::= alter_table_partitioning::= alter_external_table_clauses::= move_table_clause::= enable_disable_clause::= After each clause you will find links to its component subclauses. ...
Following the table name, specify the alterations to be made. If none are given, ALTER TABLE does nothing. The syntax for many of the permissible alterations is similar to clauses of the CREATE TABLE statement. column_definition clauses use the same syntax for ADD and CHANGE as for CREATE...