DELETE 陳述式的結果是移除表格的零或多列,視 WHERE 子句中指定的搜尋條件滿足多少列而定。 如果您省略 DELETE 陳述式中的 WHERE 子句, SQL 會從表格中移除所有列。 DELETE 陳述式看起來如下: DELETE FROM table-name WHERE search-condition ... 例如,假設部門 D11 移至另一個網站。 您可以刪除 CORPDATA.EM...
UPDATE pay_stream a SET a.return_amount = 0 WHERE a.pay_id IN (SELECT b.pay_id FROM pay_main b WHERE b.user_name = '1388888888'); id select_type table partitions type possible_keys key key_len ref rows filtered Extra --- --- --- --- --- --- --- --- --- --- ---...
内部不会真正删除空间,而且做标记删除,即将delflag:N修改为delflag:Y,commit之后会会被purge进入删除链表,如果下一次insert更大的记录,delete之后的空间不会被重用,如果插入的记录小于等于...+---+---+ 4 rows in set (0.00 sec) 删除后的SQL执行情况 #删除50w数据 mysql> delete from...50W 10.499000 7868...
delete from t where c1=5; Query OK, 1 rows affected (0.00 sec) ---TRANSACTION 146749, ACTIVE 9 sec 4 lock struct(s), heap size 1184, 3 row lock(s), undo log entries 1 MySQL thread id 1, OS thread handle 0x7f61ab1c7700, query id 104 localhost msandbox cleaning up TABLE LOCK ...
"row_may_be_null": false, "map_bit": 0, "depends_on_map_bits": [ ] } ] }, { "ref_optimizer_key_uses": [ { "table": "`yp_user`", "field": "gender", "equals": "1", "null_rejecting": false } ] }, { "rows_estimation": [ ...
rows in set (0.00 sec) #重置状态变量计数 mysql> flush status; Query OK, 0 rows affected (0.00 sec) #执行SQL语句 mysql> select id, age ,phone from user where name like 'lyn12%'; +---+---+---+ | id | age | phone | +---+---+---+ | 124 | 3 | 15240540354 | | 1231...
createtablet1 (-> idint unsignednotnullauto_increment,-> namechar(20)notnull,-> sex enum('f','m')notnulldefault'm',-> addressvarchar(30)notnull,->primarykey(id)->); Query OK,0 rows affected (0.31sec) mysql> 2.插入测试数据 ...
SQL DELETEProduction.ProductCostHistoryWHEREStandardCostBETWEEN12.00AND14.00ANDEndDateISNULL; PRINT 'Number of rows deleted is ' + CAST(@@ROWCOUNT as char(3)); C. 使用游标以确定要删除的行 以下示例使用名为EmployeePayHistory的游标删除 AdventureWorks2022 数据库的complex_cursor表中的单行。 删除操作只影...
Explanation:The DELETE statement removed a single row from the table using the WHERE clause and specifying the conditions. Method 2: Deleting Multiple Rows in SQL The DELETE statement in SQL can delete multiple rows by specifying a condition that matches more than one row. ...
使用以下SQL语句查找删除操作的事务日志记录: SELECT[TransactionID],[BeginTime],[TransactionName]FROMfn_dblog(NULL,NULL)WHERE[TransactionName]='DELETE'AND[TransactionID]IN(SELECTDISTINCT[TransactionID]FROMfn_dblog(NULL,NULL)WHERE[TransactionName]='LOP_DELETE_ROWS'); ...