create unique index index_name on table_name('column_name'); 两者区别: (1)add index_name 支持一次多个索引创建alter table table_name add index_name using btree('column_name',...,'column_name'),add index_name using btree('column_name',...,'column_name') (2)add index_name 可以创建 ...
create unique index index_name on table_name('column_name'); 两者区别: (1)add index_name 支持一次多个索引创建alter table table_name add index_name using btree('column_name',...,'column_name'),add index_name using btree('column_name',...,'column_name') (2)add index_name 可以创建 ...
CREATE INDEX index_name ON table_name(column_name) USING BTREE; [/code] If the column containsstring valuesyou can set the index to only include the first (n) characters of the string [code type=”mysql”] CREATE INDEX index_name ON table_name(column_name(n)); [/code] These variation...
alter table table_name add index_name using btree('column_name',...,'column_name');create unique index index_name on table_name('column_name');两者区别：（1）add index_name ⽀持⼀次多个索引创建alter table table_name add index_name using btree('column_name',...,'column_name')，...
mysql> # Modify the index can be instant if it's a trivial changemysql> ALTER TABLE t1 DROP KEY b, ADD KEY b(b) USING BTREE, ALGORITHM = INSTANT; Query OK, 0 rows affected (0.14 sec) Records: 0 Duplicates: 0 Warnings: 0mysql> # Rename the table through ALTER TABLE can be instan...
DFADD_USEBTREE Specifies that theB+Treeindex is used whether or not the LREC belongs in the current block. Use this parameter only if you do not expect the LREC to be added to the current block. If you do not specify this parameter, thez/TPFDF productautomatically uses theB+Treeindex ...
add_index "people", ["twitter"], name: "index_people_on_twitter", using: :btree add_index "people", ["user_id"], name: "index_people_on_user_id", using: :btree create_table "read_receipts", id: :uuid, force: :cascade do |t| create_table "read_receipts", id: :uuid, defaul...
add_index "tracks", ["playlist_id"], name: "index_tracks_on_playlist_id", using: :btree create_table "users", force: :cascade do |t| t.string "email", limit: 255, default: "", null: false t.string "encrypted_password", limit: 255, default: "", null: false @@ -46,4 +58...
ALTER TABLE.. ADD INDEX 语句用于在已有表中添加一个索引。在 TiDB 中,ADD INDEX 为在线操作,不会阻塞表中的数据读写。 语法图 语法图代码 AlterTableStmt ALTERIgnoreOptionalTABLETableNameAlterTableSpecListOptAlterTablePartitionOptANALYZEPARTITIONPartitionNameListINDEXIndexNameListAnalyzeOptionListOpt AlterTableSpe...
mysql> CREATE TABLE t1 (a INT, b INT, KEY(b)); Query OK, 0 rows affected (0.70 sec) mysql> # Modify the index can be instant if it's a trivial change mysql> ALTER TABLE t1 DROP KEY b, ADD KEY b(b) USING BTREE, ALGORITHM = INSTANT; Query OK, 0 rows affected (0.14 sec) ...