alter table table_name add index index_name(column_name); 或create index index_name on table_name(username(length)); (2)唯一索引 在创建数据表时一起创建: create table table_name(...,unique index_name(username(length))); 给数据表添加索引: alter table table_name add unique index_name(colu...
SQL ID: fpur97hs1wpp3 Plan Hash: 0 LOCK TABLE "T" IN ROW EXCLUSIVE MODE NOWAIT SQL ID: dwuf634dfa8hf Plan Hash: 0 alter table t add (sex varchar2(1)) SQL ID: 3nkd3g3ju5ph1 Plan Hash: 2853959010 select obj#,type#,ctime,mtime,stime, status, dataobj#, flags, oid$, spare1...
ALTERTABLE表名ADD索引类型 (unique,primarykey,fulltext,index)[索引名](字段名) //普通索引altertabletable_nameaddindex index_name (column_list) ;//唯一索引altertabletable_nameaddunique(column_list) ;//主键索引altertabletable_nameaddprimarykey (column_list) ; ALTER TABLE可用于创建普通索引、UNIQUE索...
在ALTER TABLE语句中,使用ADD关键字可以增加新列和完整性约束,定义方式同CREATE TABLE语句中的定义方式相同,其语法格式如下所示。ALTER TABLE <表名> ADD <列定义> | <完整性约束定义> ADD关键字后面可以是要创建列的列名、数据类型等,当然也可以对列设置非空约束和默认值。
MySQL:5.6.35 OS:redhat5.8 今天更新数据库某些表字段,有如下两SQL: ①alter table xx modify xxxx;(表大概是77w) ②alter table sb add sbsb;(表大概是95w) 奇怪的是①产生的state为:copy to tmp ta
AlterTableAddTableElementStatement AlterTableAlterColumnOption AlterTableAlterColumnStatement AlterTableAlterIndexStatement AlterTableAlterPartitionStatement AlterTableChangeTrackingModificationStatement AlterTableConstraintModificationStatement AlterTableDropTableElement AlterTableDropTableElementStatement ...
AlterTableAddTableElementStatement AlterTableAlterColumnOption AlterTableAlterColumnStatement AlterTableAlterIndexStatement AlterTableAlterPartitionStatement AlterTableChangeTrackingModificationStatement AlterTableConstraintModificationStatement AlterTableDropTableElement AlterTableDropTableElementStatement...
alter table语句中用于创建索引的子句是( ) 。A.ADD indexB.ADD keysC.modify indexD.change index的答案是什么.用刷刷题APP,拍照搜索答疑.刷刷题(shuashuati.com)是专业的大学职业搜题找答案,刷题练习的工具.一键将文档转化为在线题库手机刷题,以提高学习效率,是学习的生产
CreateExternalTableStatement CreateFederationStatement CreateFullTextCatalogStatement CreateFullTextIndexStatement CreateFullTextStopListStatement CreateFunctionStatement CreateIndexStatement CreateLoginSource CreateLoginStatement CreateMasterKeyStatement CreateMessageTypeStatement CreateOrAlterFunctionStatement CreateOrAlterProcedu...
ALTER TABLE table { [ ALTER COLUMN column_name { new_data_type [ ( precision [ , scale ] ) ] [ COLLATE < collation_name > ] [ NULL | NOT NULL ] | {ADD | DROP } ROWGUIDCOL } ] | ADD { [ < column_definition > ] | column_name AS computed_column_expression ...