Return number of rows that were deleted: Deleted 9 rows. 示例#2 计算由一个 SELECT 语句返回的行数对于大多数数据库,PDOStatement::rowCount() 不能返回受一条 SELECT 语句影响的行数。替代的方法是,使用 PDO::query() 来发出一条和原打算中的SELECT语句有相同条件表达式的 SELECT COUNT(*) 语句,然后用...
To return the number of rows that excludes the number of duplicates and NULL values, you use the following form of the COUNT() function: COUNT(DISTINCT column)Code language: SQL (Structured Query Language) (sql) To return the number of rows that includes the number of duplicates and excludes...
For UPDATE, INSERT, and DELETE statements, the return value is the number of rows affected by the command. When a trigger exists on a table being inserted or updated, the return value includes the number of rows affected by both the insert or update operation and the number of rows affecte...
Number of rows affected by the SQL statement, when process is successful. -1, when SQL statement is not INSERT, DELETE or UPDATE. false, when the request identifier is not specified, and there is no last request. 范例 示例#1 cubrid_affected_rows() example <?php$conn = cubrid_connect...
Number of rows affected by the SQL statement, when process is successful. -1, when SQL statement is not INSERT, DELETE or UPDATE. FALSE, when the request identifier is not specified, and there is no last request. 范例 Example #1cubrid_affected_rows()example ...
It is possible to delete all rows in a table without deleting the table. This means that the table structure, attributes, and indexes will be intact:DELETE FROM table_name(customers); The SELECT TOP clause specify the number of records to return 指定要返回的记录数,数据量很大时用得多 ...
/// /// <returns>True if and only if there is data to read</returns> public bool ReadPrevious() { EnsureScroll(); return fetch(string.Format(CultureInfo.InvariantCulture, "FETCH PREVIOUS FROM {0};", cursorName)); } /// /// Move the specified number of records forward or backward...
GO SELECT * FROM TestBatch; -- Returns rows 1 and 2. GO 锁定和行版本控制基本知识 当多个用户同时访问数据时,数据库引擎使用以下机制确保事务的完整性和保持数据库的一致性: 锁定 每个事务对所依赖的资源(如行、页或表)请求不同类型的锁。 锁可以阻止其他事务以某种可能会导致事务请求锁出错的方式修改资...
Return Types bigint Remarks The ORDER BY clause determines the sequence in which the rows are assigned their unique ROW_NUMBER within a specified partition. Examples A. Returning the row number for salespeople The following example returns theROW_NUMBERfor the salespeople inAdventureWorksbased on the...
此缓冲区的地址是使用 SQL_ATTR_ROWS_FETCHED_PTR 语句属性指定的。 缓冲区由应用程序分配。 它由SQLFetch和SQLFetchScroll设置。 如果 SQL_ATTR_ROWS_FETCHED_PTR 语句属性的值是空指针,则这些函数不会返回提取的行数。 若要确定结果集中当前行的数目,应用程序可以使用 SQL_ATTR_ROW_NUMBER 属性调用SQLGetStmtAtt...