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
如果SQL 在執行 DELETE 陳述式時發現錯誤,則會停止刪除資料並傳回負 SQLCODE。 如果您指定 COMMIT (*ALL)、COMMIT (*CS)、COMMIT (*CHG) 或 COMMIT (*RR) ,則不會刪除表格中的任何橫列 (此陳述式已刪除的橫列 (如果有的話) 會還原為先前的值)。 如果指定 COMMIT (*NONE) ,任何已刪除的橫列 不會 還...
首先,DELETE不是不能用,而是你得知道它的代价,你得知道它背后到底做了啥。很多人写个SQL就是: DELETE FROM user WHERE status = 'inactive'; 看着清清爽爽,执行完了控制台还给你来句“Query OK, 1000000 rows affected”,然后服务嘎的一声宕机,QPS跌成狗,DBA头发开始谢落,领导问你是不是手滑了。 这波操作,...
SQL SELECT TOP 子句 SQL Server / MS Access 语法: SELECTTOP number|percentcolumn_name(s) FROMtable_name WHEREcondition; MySQL 语法: SELECTcolumn_name(s) FROMtable_name WHEREcondition LIMIT number; Oracle 12 语法: SELECTcolumn_name(s) FROMtable_name ORDERBYcolumn_name(s) FETCHFIRSTnumberROWSONL...
-- 开始一个事务BEGINTRANSACTION;-- 假设执行了误删除操作DELETEFROMemployeesWHEREid=1;-- 查看日志中的操作记录SELECT*FROMfn_dblog(NULL,NULL)WHEREOperation='LOP_DELETE_ROWS';-- 如果确认要撤销,则可以进行回滚ROLLBACKTRANSACTION; 1. 2. 3.
Learn-SQL/ MySQL/ How to Delete in MySQL How to Delete in MySQL To delete rows in a MySQL table, use the DELETE FROM statement: DELETE FROM products WHERE product_id=1; The WHERE clause is optional, but you'll usually want it, unless you really want to delete every row from the tab...
UPDATE pay_stream a LEFT JOIN pay_main b ON a.pay_id = b.pay_id AND b.pay_time >= '2017-08-12 00:00:00' SET a.return_amount = 0 WHERE b.pay_id IS NULL; id select_type table partitions type possible_keys key key_len ref rows filtered Extra --- --- --- --- --- -...
-- 使用系统函数和视图查看已删除的数据SELECT[CurrentLSN],[TransactionID],[BeginTime],[EndTime],[TransactionName],[TransactionSID]FROMsys.fn_dblog(NULL,NULL)WHERE[Operation]='LOP_DELETE_ROWS'AND[AllocUnitName]='dbo.TestTable' 1. 2.
“MySQL DELETE并不推荐直接在大表上用，是因为InnoDB的事务机制、日志机制、MVCC机制决定了DELETE开销大...
{ "table": "`yp_user`", "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": [ { "table"...