上述SQL语句的含义是,从users表中删除所有不在blacklist表中的行。NOT EXISTS子句用来限定只保留在blacklist表中不存在的行。 解释 DELETE FROM:表示要删除哪张表的数据 WHERE NOT EXISTS:NOT EXISTS是一个谓词子句,该子句与WHERE一起使用,用于删除不在黑名单中的用户。
In this query, we are selecting all columns from theemployeestable where theemployee_idis not present in thesalestable. Conclusion Using theWHERE NOT EXISTSclause can be a powerful tool when working with databases. It allows us to extract data that is not present in another table. This can ...
Finding Records in One table that Don't Exist in Another Table (the Not-In Query) Now assume that we ONLY want to find the customers who have not placed any orders. Just like in the first scenario, we will use a Left Outer Join to accomplish this. This time, however, we’ll add ...
How to SELECT data from a table which is not present in another table with SQL is a common operation in databases. There are many ways to query this, like usingNOT IN andNOT EXISTS. But the most efficient way is to useLEFT JOIN. CREATETABLEbasket1(idINTIDENTITY(1,1),fruitVARCHAR(20...
SQL 复制 SELECT name FROM mytable WHERE name = 'Bill'; 键范围锁放置在与从 Ben 到Bing 的名称范围对应的索引项上,因为名称 Bill 将插入到这两个相邻的索引项之间。 RangeS-S 模式键范围锁放置在索引项 Bing 上。 这样可阻止其他任何事务在索引项 Bill 与Ben 之间插入值(例如 Bing)。
The CTE result set is derived from a simple query and is referenced by UPDATE statement.Common table expressions can also be used with the SELECT, INSERT, DELETE, and CREATE VIEW statements. For more information, see WITH common_table_expression (Transact-SQL)....
DELETE mytable WHERE name = 'Bob'; TID ロックは、トランザクションの期間中、変更されたすべての行に対して行われます。 値 Bobに対応するインデックス 行の TID に対してロックが取得されます。 最適化されたロックでは、ページロックと行ロックは更新のために引き...
Add prefix in data column Add Time in SQL HH:MM:SS to another HH:MM:SS Adding a column to a large (100 million rows) table with default constraint adding a extra column in a pivot table created uisng T-SQL Pivot Table query Adding a partition scheme to an existing table. Adding a...
14、一个的 query2.EXISTS 在此是指存在与否SELECT *FROM table_name1WHERE column1 IN (SELECT column1 FROM table_name2WHERE conditions )说明1. IN 後面接的是一个集合,表示column1 存在集合里面2. SELECT 出来的资料形态必须符合 column1 其他查询SELECT *FROM 15、60;table_name1WHERE column1 LIKE ...
8005 HY000 Table '%s' not found 表不存在,请检查表的名称是否有误。 8006 HY000 Query failed; %s 查询失败,请根据错误消息分析错误原因。 若依然无法解决,请联系Lindorm技术支持寻求解决方法。 8007 HY000 Insert failed; %s 写入失败,请根据错误消息分析错误原因。 若依然无法解决,请联系Lindorm技术支持寻求解决...