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  • 在本教程中,您将学习如何使用SQL DELETE语句删除表中的一行或多行。1. SQL DELETE语句简介要从表中删除一行或多行,请使用DELETE语句DELETE语句的一般语法如下:DELETEFROMtable_nameWHEREcondition;首先,提供...

    在本教程中,您将学习如何使用SQL DELETE语句删除表中的一行或多行。

    1. SQL DELETE语句简介

    要从表中删除一行或多行,请使用DELETE语句。 DELETE语句的一般语法如下:

    DELETE

    FROM

    table_name

    WHERE

    condition;

    首先,提供要删除行的表名称(table_name)。

    其次,在WHERE子句中指定条件以标识需要删除的行记录。 如果省略WHERE子句,则将删除表中的所有行记录。 因此,应始终谨慎使用DELETE语句。

    一般来说,DELETE语句不会将结果集。 但是,它只返回已删除的行数。

    2. SQL DELETE语句示例

    我们将使用employees和dependents表来演示DELETE语句。

    9c77e3138520657628783829c879e386.png

    2. SQL删除表中的一行

    使用以下DELETE语句从dependents表中删除ID为:16的行记录。

    DELETE FROM dependents

    WHERE

    dependent_id = 16;

    由于WHERE子句包含主键表达式,因此DELETE语句只删除一行。可以使用以下语句验证是否已删除dependents中ID为:16的行记录:

    SELECT

    COUNT(*)

    FROM

    dependents

    WHERE

    dependent_id = 16;

    3. SQL DELETE多行示例

    要删除表中的多个行记录,请使用WHERE子句中的条件来选择要删除的行记录。 例如,以下语句使用IN运算符来删除dependents表中id为100,101或102的信息。

    DELETE FROM dependents

    WHERE

    employee_id IN (100 , 101, 102);

    4. SQL DELETE来自相关表的行

    一名员工可能有零个或多个家属,而一个受抚养人只属于一名员工。 dependents表中的employee_id列链接到employees表中的employee_id列。

    员工与家属表之间的关系是一对多的。

    从逻辑上讲,如果不引用员工,就不能存在依赖关系。 换句话说,当删除员工信息时,他/她的家属也必须要删除。

    例如,要删除员工ID为199和所有员工的依赖项,需要执行两个DELETE语句,如下所示:

    DELETE

    FROM

    employees

    WHERE

    employee_id = 199;

    DELETE

    FROM

    dependents

    WHERE

    employee_id = 199;

    大多数数据库系统都支持外键约束,因此当删除表中的一行时,外键表中的行也会自动删除。

    因此,执行以下DELETE语句时:

    DELETE

    FROM

    employees

    WHERE

    employee_id = 199;

    在执行上面语句后,employee_id为199的所有行也会自动删除。

    要更有效地从表中删除所有行,可以使用TRUNCATE TABLE语句,而不是使用不带WHERE子句的DELETE语句。

    通过上面的示例和学习,您应该了解SQL DELETE语句用法,以及如何应用它来删除表中的一行或多行。

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  • sql delete语句 This article on the SQL Delete is a part of the SQL essential series on key statements, functions and operations in SQL Server. 有关SQL Delete的这篇文章是有关SQL Server中关键语句...

    sql delete语句

    This article on the SQL Delete is a part of the SQL essential series on key statements, functions and operations in SQL Server.

    有关SQL Delete的这篇文章是有关SQL Server中关键语句,函数和操作SQL基本系列的一部分。

    To remove a row from a table is accomplished through a Data Manipulation Language, aka DML statement, using the delete keyword. The SQL delete operation is by far the simplest of all the DML commands. On execution of the delete command, we don’t have to worry about getting any form of data from the table, and we don’t have to worry about working with any data that we get back from the table(s). We just simply tell the database to delete a specific record, and it either does or it doesn’t. It’s that simple.

    从表中删除行是通过数据操作语言(又称DML语句)使用delete关键字完成的。 到目前为止,SQL删除操作是所有DML命令中最简单的操作。 在执行delete命令时,我们不必担心从表中获取任何形式的数据,也不必担心处理从表中获取的任何数据。 我们只是简单地告诉数据库删除特定记录,它要么执行,要么不执行。 就这么简单。

    First, let’s quickly review what an SQL delete statement looks like. We need to tell the database and table from where it should delete the data. It’s a good idea to add a condition clause to set the scope of data deletion. Otherwise, it will delete everything in the table.

    首先,让我们快速回顾一下SQL delete语句的外观。 我们需要告诉数据库和表应从何处删除数据。 添加条件子句以设置数据删除的范围是一个好主意。 否则,它将删除表中的所有内容。

    Let’s take a look at our table and removing some records.

    让我们看一下表并删除一些记录。

    如何删除不带where子句的行 (How to delete rows with no where clause)

    The following example deletes all rows from the Person.Person the table in the AdventureWorks2014 database. There is no restriction enforced on the SQL delete statement using a WHERE clause.

    下面的示例从AdventureWorks2014数据库中的Person.Person表中删除所有行 。 使用WHERE子句SQL delete语句没有任何限制。

    USE Adventureworks2014;
    GO
    DELETE FROM [Person].[Person];
    

    如何使用where子句删除行 (How to delete rows with where clause)

    The following example deletes rows from the [Person].[Person] table in the AdventureWorks2014 database in which the value in the businessEntityID column is greater than 30,000

    以下示例从AdventureWorks2014数据库的[Person]。[Person]表中删除行,其中businessEntityID列中的值大于30,000

    USE Adventureworks2014;
    GO
    DELETE FROM [Person].[Person]
    WHERE businessEntityID > 30000;
    

    Note: An unfortunate mistake that may occur is to accidently run a SQL Delete with no Where clause and inadvertently delete all of your data. To prevent this from happening consider using the Execution guard feature in ApexSQL Complete, to warn against such potentially damaging actions, before you execute them. Learn more: Execution alerts

    注意:可能发生的不幸错误是意外地运行了不带Where子句SQL Delete并无意间删除了所有数据。 为防止这种情况发生,请在执行之前考虑使用ApexSQL Complete中的Execution保护功能,以警告此类可能有害的操作。 了解更多: 执行警报

    如何使用带有where子句的Top删除行 (How to delete rows using Top with where clause)

    The following example deletes 50 random rows from the Person.Person table in the AdventureWorks2014 database. The value in the BusinessEntityID must be in between 30,000 and 40,000

    下面的示例从AdventureWorks2014数据库的Person.Person表中删除50个随机行。 BusinessEntityID中的值必须介于30,000和40,000之间

    USE Adventureworks2014;
    GO
    DELETE TOP(50) FROM [Person].[Person]
    WHERE BusinessEntityID between 30000 and 40000
    

    Note: The when the TOP (n) clause is used with the SQL Delete statement and any DML statement (i.e. Select, Insert, Delete and Update), the operation is performed on a random selection of a number of rows specified in the Top clause.

    注意:当TOP(n)子句与SQL Delete语句和任何DML语句(即Select,Insert,Delete和Update)一起使用时,将对Top子句中指定的许多行的随机选择执行操作。

    如何删除重复的行 (How to delete duplicate rows)

    In the real-world, we tend to gather data from different sources; it’s not uncommon to have duplicate records. One approach to the duplicate problem is first to identify where the duplicates have occurred. And run a select query on those columns.

    在现实世界中,我们倾向于从不同的来源收集数据。 有重复的记录并不少见。 解决重复问题的一种方法是首先确定重复发生在哪里。 并对这些列运行选择查询。

    EATE TABLE tb_spaceused
    (database_name       NVARCHAR(128), 
     database_size       VARCHAR(18), 
     [unallocated space] VARCHAR(18), 
     reserved            VARCHAR(18), 
     data                VARCHAR(18), 
     index_size          VARCHAR(18), 
     unused              VARCHAR(18)
    );
    INSERT INTO tb_spaceused
    EXEC sp_msforeachdb 
         @command1 = "use ? exec sp_spaceused  @oneresultset = 1";
     
    SELECT *
    FROM tb_spaceused
    order by database_name
    

    The following example uses the PARTITION BY argument to partition the query result set by all the columns of tb_spaceused table. The Row_Number (), a window function, which means it operates over an ordered set. The ORDER BY clause specified in the OVER clause orders the rows in each partition by the entire columns tb_spaceused table.

    以下示例使用PARTITION BY参数将查询结果集按tb_spaceused表的所​​有列进行分区 。 Row_Number()是一个窗口函数,这意味着它将对有序集进行操作。 OVER子句中指定的ORDER BY子句按tb_spaceused表的整个列对每个分区中的行进行排序。

    WITH CTE
         AS (SELECT *, 
                    ROW_NUMBER() OVER(PARTITION BY database_name, 
                                                   database_size, 
                                                   [unallocated space], 
                                                   reserved, 
                                                   data, 
                                                   index_size, 
                                                   unused
                    ORDER BY database_name
                            ) AS Row_Num
             FROM tb_spaceused)
         SELECT *
         FROM CTE
         WHERE Row_Num <> 1;
    

    The following example uses the PARTITION BY argument to partition the query result set by all the columns of tb_spaceused table.

    Replacing the Select statement with a Delete removes all the duplicates of the table.

    用Delete替换Select语句将删除表的所有重复项。

    WITH CTE
         AS (SELECT *, 
                    ROW_NUMBER() OVER(PARTITION BY database_name, 
                                                   database_size, 
                                                   [unallocated space], 
                                                   reserved, 
                                                   data, 
                                                   index_size, 
                                                   unused
                    ORDER BY database_name
                            ) AS Row_Num
             FROM tb_spaceused)
         --SELECT *
         --FROM CTE
         --WHERE Row_Num <> 1;
    	 DELETE FROM CTE
         WHERE Row_Num <> 1;
    

    Replacing the Select statement with a Delete removes all the duplicates of the table.

    如何使用SQL子查询删除行 (How to delete rows using SQL sub-queries)

    In the following example, the rows in one table are deleted based on data in another table. In the examples, the rows from the SalesPersonQuotaHistory table are deleted based on the SalesYTD column of the SalesPerson table.

    在以下示例中,一个表中的行基于另一表中的数据被删除。 在示例中,根据SalesPerson表的SalesYTD列删除SalesPersonQuotaHistory表中的行。

    DELETE FROM Sales.SalesPersonQuotaHistory
    WHERE BusinessEntityID IN
    (
        SELECT BusinessEntityID
        FROM Sales.SalesPerson
        WHERE SalesYTD > 4900000.00
    ); 
    GO
    

    如何使用SQL联接删除行 (How to delete rows using SQL Joins )

    In this section, we will use the SQL Delete statement to delete the data from the Adeventureworks2014 database. Deleting data, at first sight, sound trivial, but once we get into a large database design things might not be same and easy anymore.

    在本节中,我们将使用SQL Delete语句从Adeventureworks2014数据库中删除数据。 乍一看,删除数据似乎微不足道,但是一旦我们进入大型数据库设计,事情可能就不再那么简单了。

    In many cases, the tables are related via a primary and foreign key relationship. In the following example, we can see a use of joins to delete the data from the Sales.SalesPersonQuotaHistory.

    在许多情况下,这些表通过主键和外键关系进行关联。 在以下示例中,我们可以看到使用联接从Sales.SalesPersonQuotaHistory中删除数据

    DELETE sq
    FROM Sales.SalesPersonQuotaHistory sq
         INNER JOIN Sales.SalesPerson sp ON sq.BusinessEntityID = sp.BusinessEntityID
    WHERE sp.SalesYTD > 4500000.00;  
    GO
    

    如何使用链接的服务器和OpenQuery从远程表中删除行 (How to delete rows from a remote table using linked servers and OpenQuery)

    The following example uses the SQL delete statement to delete rows from a remote table using the linked server named, hqdbt01. Then query the remote table using four-part object naming convention to delete the rows from the remote table

    下面的示例使用SQL delete语句使用名为hqdbt01的链接服务器从远程表中删除行。 然后使用四部分对象命名约定查询远程表以从远程表中删除行

    DELETE
    FROM [hqdbt01].AdventureWorks2014.[HumanResources].[Shift]
    WHERE ShiftID = 2;
    

    The following example, the remote table is queried by specifying the OPENQUERY rowset function along with the delete command.

    在以下示例中,通过指定OPENQUERY行集函数以及delete命令来查询远程表。

    DELETE OPENQUERY (hqdbt01, 'SELECT *
    FROM AdventureWorks2014.HumanResources.Department  
    WHERE DepartmentID = 18');
    

    如何使用SSMS删除行 (How to delete rows using SSMS)

    Using the SQL Server Management Studio (SSMS), Graphical User Interface (GUI) to delete rows involves a manual search. In reality, it will be much easier and quicker to delete records with a SQL query.

    使用SQL Server Management Studio(SSMS),图形用户界面(GUI)删除行涉及手动搜索。 实际上,使用SQL查询删除记录将更加容易和快捷。

    Let’s go ahead and locate the table to use a SQL delete statement, in this case, table dbo.cities is selected. Now, right-click and choose Edit Top 200 rows. This option opens up a query designer window. Next, right-click the window and select Execute SQL and write a new query that will delete rows from the dbo.cities table.

    让我们继续查找表以使用SQL delete语句,在这种情况下,将选择表dbo.cities 。 现在,右键单击并选择编辑前200行 。 此选项将打开查询设计器窗口。 接下来,右键单击该窗口并选择Execute SQL并编写一个新查询,该查询将从dbo.cities表中删除行。

    How to delete rows using SSMS

    In the result pane, make sure that SELECT Statement is pulling up the correct targeted records before start deleting rows. Select the rows and right-click the rows and choose Delete to remove the rows from the table.

    在结果窗格中,在开始删除行之前,请确保SELECT语句提取正确的目标记录。 选择行并右键单击行,然后选择“ 删除”以从表中删除行。

    SQL delete - Select the rows and right-click the rows and choose Delete to remove the rows from the table.

    摘要 (Summary)

    Thus far, we’ve seen many different ways use the SQL delete statement to remove data. But, there is a list of the consideration to be followed while using the delete statement, and it as follows:

    到目前为止,我们已经看到使用SQL delete语句删除数据的许多不同方式。 但是,在使用delete语句时,有一个注意事项列表,如下所示:

    1. It is always recommended to start with a SELECT statement before you delete anything to make sure that you’re targeting the correct records. So the delete statement is used to delete rows from a table using the where clause to select only the rows to be deleted

      始终建议从SELECT语句开始,然后再删除任何内容,以确保定位的是正确的记录。 因此,delete语句用于使用where子句从表中删除行,以仅选择要删除的行
    2. Always use a unique identifier to locate the rows that you need to delete

      始终使用唯一标识符查找需要删除的行
    3. To delete all the rows in a table, always use TRUNCATE TABLE. TRUNCATE TABLE which is faster than a SQL delete statement and it uses fewer system and transaction-log resources

      要删除表中的所有行,请始终使用TRUNCATE TABLE。 TRUNCATE TABLE比SQL delete语句快,并且使用较少的系统和事务日志资源
    4. By default, DELETE statements induce an exclusive (X) lock on the table, and it holds the lock until the transaction completes

      默认情况下,DELETE语句在表上引入互斥(X)锁,并持有该锁,直到事务完成为止
    5. NOLOCK hint or read uncommitted NOLOCK提示或读取未提交的isolation level 隔离级别允许读取操作
    6. It is recommended to specify the TABLOCK hint in the delete statement. This process allows page de-allocation and associated space available for reuse by other objects in the database

      建议在delete语句中指定TABLOCK提示。 此过程允许页面解除分配以及相关的空间可用于数据库中的其他对象重用
    7. It is good practice to create a clustered index on the heap table before executing a delete statement

      优良作法是在执行删除语句之前在堆表上创建聚簇索引
    8. Although very simple and very powerful, and the result of a Delete statement is destructive. Deleted rows cannot be easily recovered

      尽管非常简单且非常强大,但Delete语句的结果却具有破坏性。 删除的行无法轻易恢复

    Note: To recover deleted rows see SQL Server disaster recovery – How to quickly recover data lost due to an Inadvertent delete operation

    注意:要恢复已删除的行,请参阅SQL Server灾难恢复–如何快速恢复由于无意删除操作而丢失的数据

    That’s all for now… Hope you enjoy reading this article on the SQL delete statement. If you have any questions, feel free to comment below.

    现在就这些了……希望您喜欢阅读有关SQL delete语句的本文。 如有任何疑问,请在下面发表评论。

    翻译自: https://www.sqlshack.com/overview-of-the-sql-delete-statement/

    sql delete语句

    展开全文
  • SQL DELETE 语句

    2017-12-19 14:53:00
    SQLDELETE语句 DELETE 语句用于删除表中的记录。 SQL DELETE 语句 DELETE 语句用于删除表中的行。 SQL DELETE 语法 DELETE FROM table_name WHERE some_column=some_value; 请...

    SQL DELETE 语句


    DELETE 语句用于删除表中的记录。


    SQL DELETE 语句

    DELETE 语句用于删除表中的行。

    SQL DELETE 语法

    DELETE FROM table_name
    WHERE some_column=some_value;

     

     

    lamp 请注意 SQL DELETE 语句中的 WHERE 子句!
    WHERE 子句规定哪条记录或者哪些记录需要删除。如果您省略了 WHERE 子句,所有的记录都将被删除!

     


    演示数据库

    在本教程中,我们将使用 RUNOOB 样本数据库。

    下面是选自 "Websites" 表的数据:

    +----+--------------+---------------------------+-------+---------+
    | id | name         | url                       | alexa | country |
    +----+--------------+---------------------------+-------+---------+
    | 1  | Google       | https://www.google.cm/    | 1     | USA     |
    | 2  | 淘宝          | https://www.taobao.com/   | 13    | CN      |
    | 3  | 菜鸟教程      | http://www.runoob.com/    | 4689  | CN      |
    | 4  | 微博          | http://weibo.com/         | 20    | CN      |
    | 5  | Facebook     | https://www.facebook.com/ | 3     | USA     |
    |  6 | 百度         | https://www.baidu.com/    |     4 | CN      |
    |  7 | stackoverflow | http://stackoverflow.com/ |     0 | IND     |
    +----+---------------+---------------------------+-------+---------+

     

     


    SQL DELETE 实例

    假设我们要从 "Websites" 表中删除网站名为 "百度" 且国家为 CN 的网站 。

    我们使用下面的 SQL 语句:

    实例

    DELETE FROM Websites WHERE name='百度' AND country='CN';

     

    执行以上 SQL,再读取 "Websites" 表,数据如下所示:


    删除所有数据

    您可以在不删除表的情况下,删除表中所有的行。这意味着表结构、属性、索引将保持不变:

    DELETE FROM table_name;



    DELETE * FROM table_name;

     

    注释:在删除记录时要格外小心!因为您不能重来!

    转载于:https://www.cnblogs.com/cisum/p/8065657.html

    展开全文
  • SQL语句-delete语句

    2017-11-30 11:14:00
    delete语句 delete语句用于删除表中已经存在的整行数据 Tbl_name关键词代表删除数据的目标表 Where子句代表被删除数据的满足条件,如果没有where子句则代 表所有表数据都删除 Order by子句代表删除数据的顺序 Limit...

    delete语句

    • delete语句用于删除表中已经存在的整行数据
    • Tbl_name关键词代表删除数据的目标表
    • Where子句代表被删除数据的满足条件,如果没有where子句则代
    • 表所有表数据都删除
    • Order by子句代表删除数据的顺序
    • Limit子句代表被删除数据的行数限制

    • delete单表删除举例

      Delete from students;
      delete from students where sid=1; 
      Delete from students order by sid; 
      Delete from students limit 1;       -- 只删除先找到的一行

    多表删除语句语法有以下两种

    • 同样,被删除的表不能出现在查询子句的子查询中
    • Low_priority关键词表示删除语句需要等待其他链接的读此表操作
    • 结束后再执行,只作用在MyISAM, MEMORY, and MERGE存储引擎
    • Quick关键词是在使用myisam存储引擎时,删除操作不会合并删
    • 除表的索引叶节点,这样会在一定程度上加快删除的速度
    • ignore关键词代表会忽略删除过程中的一些错误

    order by子句

    • Delete语句中的order by子句决定了删除数据的顺序,配合limit子 句后在某些情况下也非常有用,比如删除最老的一条记录:
    DELETE FROM somelog WHERE user = 'jcole' ORDER BY timestamp_column LIMIT 1;
    • 多表删除是指从一个或多个表中删除满足条件的数据,其中的 table_references代表了多个表的join操作,例如以下两个例子代表
    • 从t1和t2表中删除满足条件的数据
    DELETE t1, t2 FROM t1 INNER JOIN t2 INNER JOIN t3
    WHERE t1.id=t2.id AND t2.id=t3.id;
    DELETE FROM t1, t2 USING t1 INNER JOIN t2 INNER JOIN t3
    WHERE t1.id=t2.id AND t2.id=t3.id;
    • 对多表删除语句而言,如果想对表使用别名,则只能在 table_references子句中使用,否则会报错

      DELETE a1, a2 FROM t1 AS a1 INNER JOIN t2 AS a2 WHERE a1.id=a2.id;      -- 正确
      DELETE FROM a1, a2 USING t1 AS a1 INNER JOIN t2 AS a2 WHERE a1.id=a2.id;    -- 正确
      DELETE t1 AS a1, t2 AS a2 FROM t1 INNER JOIN t2 WHERE a1.id=a2.id;      -- 错误
      DELETE FROM t1 AS a1, t2 AS a2 USING t1 INNER JOIN t2 WHERE a1.id=a2.id;    -- 错误

    练习

    • 删除所有学号大于200的学生信息
    • 删除系名为accounting的所有老师信息
    展开全文
  • Oracle SQLdelete删除语句总结

    万次阅读 2015-03-27 16:40:40
    Oracle delete sql 语句总结:1、delete 用于删除表中的某行或整个数据表中的数据;2、 truncate也可用于删除整个表里面的数据,truncate释放空间,速度更快
  • 文章目录SQL INSERT INTO 语句SQL UPDATE 语句SQL DELETE 语句 SQL INSERT INTO 语句 NSERT INTO 语句用于向表中插入新记录。 NSERT INTO 语句可以有两种编写形式。 第一种形式无需指定要插入数据的列名,只需提供被...
  • SQL语句DELETE

    2017-03-13 13:51:07
    DELETEDELETE语句用于删除表中的行, 语法DELETE FROM 表名称 WHERE 列名称 = 值CAR表: VIN BRAND MODEL PRICE PRODUCTION_YEAR LJCPCBLCX14500264 Ford Focus 8000 2005 WPOZZZ79ZTS372128 Ford ...
  • ……SELECT查询语句SQL的核心,聊完了它,剩下的就简单了……掰掰我的手指头……关于SQL,我们大概还有3个部分没讲,分别是DELETE删除、UPDATE更新以及INSERT新增。这3个语句讲完,本系列的SQL也就告一段...
  • SQL DELETE 语句详解

    2019-09-22 13:38:17
    SQL DELETE 语句详解 DELETE 语句 DELETE 语句用于删除表中的行。 语法 DELETE FROM 表名称 WHERE 列名称 = 值 Person: LastNameFirstNameAddressCity Gates Bill Xuanwumen 10 Beijing...
  • SQL数据库介绍转眼已进入12月下旬不忘初心,继续前行今天我们来学习VB与数据库编程中的SQL语句。SQL简介SQL数据库语言是一种通用的,功能强大的关系型数据库语言,是操作数据库的行业编程,使用SQL语言能够方便地对...
  • sql delete语句

    千次阅读 2018-03-21 11:25:17
    delete语句用于删除数据库的表 delete语句结构:delete from 表名 where 字段1=值1 delete from person where name="liuliu"//删除表中的名字为liuliu的行  
  • SQL DELETE语句

    千次阅读 热门讨论 2017-05-01 10:52:33
    Delete语句 Delete语句用于删除表中的行 语法: DELETE FROM 表名称 WHERE 列名称 = 值 User: 删除某行 例如:"userID 2910"会被删除 DELETE FORM User WHERER userID = “2910”  结果: 删除所有行 ...
  • SQL DELETE 语句 DELETE 语句用于删除表中的行。 SQL DELETE 语法 DELETE FROM table_name WHERE some_column=some_value;   请注意 SQL DELETE 语句中的 WHERE 子句! WHERE 子句规定哪条记录或者...
  • DELETE 作用DELETE语句用于删除...注意SQL DELETE 语句中的 WHERE 子句!WHERE子句指定需要删除哪些记录。如果省略了WHERE子句,表中所有记录都将被删除!示例数据库以下是 "Customers" 表中的数据:DELETE 实例在删...
  • 深入理解select语句、SQL语句 我们从一个例子出发:删除表中字段的语句:(以mysql5.5数据库为例) 1,delete from user as u where u.userid=6; 2,delete from user u where u.userid=6; 3,delete from user ...
  • SQL : DELETE 语句

    2019-07-08 15:23:03
    SQL DELETE 语句 DELETE 语句用于删除表中的行。 SQL DELETE 语法 DELETE FROM table_name WHERE some_column=some_value; lamp 请注意 SQL DELETE 语句中的 WHERE 子句! WHERE 子句规定哪条记录或者哪些记录需要...
  • sql语句delete

    2020-07-20 19:26:36
    delete语句用于删除表中已经存在的整行数据 • Tbl_name关键词代表删除数据的目标表 • Where子句代表被删除数据的满足条件,如果没有where子句则代 表所有表数据都删除 • Order by子句代表删除数据的顺序 • Limit...

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