...)] {VALUES} ({expr | DEFAULT},...),(...),... [ ON DUPLICATE KEY UPDATE ...
3.通常insert操作是不加锁的,但如果在插入或更新记录时,检查到 duplicate key(或者有一个被标记删除的duplicate key),对于普通的insert/update,会加S锁,而对于类似replace into或者insert … on duplicate 这样的SQL语句加的是X锁。 4.insert … select 插入数据时,会对 select 的表上扫描到的数据加S锁; 5....
INSERTINTO<target>VALUES<wa>.INSERT<target>FROM<wa>. 多条数据. INSERT<target>FROMTABLE<itab> [ACCEPTING DUPLICATE KEYS] 插入数据时,避免有相同主键引起dump error错误,使用ACCEPTING DUPLICATE。此时sy-subrc返回4. 三、UPDATE 一条数据 UPDATE<target>FROM<wa>."表结构相同 多条数据. UPDATE<target>FROMT...
Select Distinct in SQL A column often contains many duplicate values, and sometimes the information needed from a single column has to be distinct. Using the SELECT DISTINCT statement inSQL, we can filter out distinct values from a column. ...
SQL select distinct on multiple columns is more useful in an RDBMS system to fetch unique records from various columns in a single table. We can use SQL to select distinct keywords on multiple columns from the specified table defined in the query. It will remove duplicate records from the col...
Answer: C.SQL statements are not case sensitive. Column Heading Defaults: 默认的列标题(表的第一行): Arithmetic expressionsandNULLvalues in theSELECTstatement SELECT语句中的算术表达式和空值 首先介绍显示表结构的命令 DESCRIBEcommand 描述命令:显示表结构 ...
Whereas, a regularSELECTstatement without theDISTINCTkeyword retrieves all rows from the specified columns, including duplicate values. Let's look at an example. Example: SELECT DISTINCT -- select distinct countries from the Customers tableSELECTDISTINCTcountryFROMCustomers; ...
SQL Server 使用select [duplicate]分组除了聚集之外，您SELECT的任何列都应放在GROUP BY子句中 ...
The database engine typically sorts the result set based on the specified columns and then eliminates duplicate rows to produce the final distinct result set. Check out our 1000+ SQL Exercises with solution and explanation to improve your skills. ...
The result of INTERSECT does not contain any duplicate rows. The INTERSECT clause has the following constraints: Multiple INTERSECT operators in the same SELECT statement are evaluated left to right, unless otherwise specified by parentheses. Processing INTERSECT preferentially when UNION and INTERSECT ...