lnameVARCHAR(20));SELECTidAS"编号",nameAS"姓名"FROMt_stu; #起别名时,as可以省略SELECTidAS编号,nameAS姓名FROMt_stu; #别名中没有空格时,""可以省略SELECTidAS编 号,nameAS"姓名"FROMt_stu; #错误,别名中有空格时,""不可以省略SELECTidAS"编号",nameAS"姓名"FROMt_stu; #这一条才最符合SQL编写规范...
代码语言:sql 复制 SELECT * FROM Customers FETCH FIRST 3 ROWS ONLY; 使用旧版 Oracle 的 ROWNUM 以下SQL 语句展示了旧版 Oracle 的等效示例: 选择"Customers" 表的前 3 条记录: 代码语言:sql 复制 SELECT * FROM Customers WHERE ROWNUM <= 3; 添加WHERE 子句 以下SQL 语句从 "Customers" 表中选择前三...
FETCH FIRST 5 ROWS ONLY就会按字面的意思去做的(只取前 5 行)。 如果你使用 Oracle,需要基于ROWNUM(行计数器)来计算行,像这样: SELECTprod_name FROMProducts WHEREROWNUM<=5; 如果你使用 MySQL、MariaDB、PostgreSQL 或者 SQLite,需要使用LIMIT子句,像这样: SELECTprod_name FROMProducts LIMIT5; 上述代码使用S...
LIMIT3; Try it Yourself » The following SQL statement shows the equivalent example for Oracle: Example SELECT*FROMCustomers ORDERBYCustomerNameDESC FETCHFIRST3ROWS ONLY; Exercise? What would the following query do in SQL Server? SELECT TOP 5 * FROM Customers; ...
This first code example returns all rows (no WHERE clause is specified) and all columns (using the *) from the Product table in the AdventureWorks2022 database.SQL Copy USE AdventureWorks2022; GO SELECT * FROM Production.Product ORDER BY Name ASC; -- Alternate way. USE AdventureWorks2022; ...
SQL 複製 SELECT --C.3 o.object_type AS [Type-of-Item], p.name AS [Package], o.name AS [Item], o.description AS [Item-Description] FROM sys.dm_xe_objects AS o JOIN sys.dm_xe_packages AS p ON o.package_guid = p.guid WHERE o.object_type IN ('action' , 'target' , '...
SELECTTOP3WITHTIESfirst_name, countryFROMCustomersORDERBYcountryDESC; Here, the SQL command, first sorts the rows bycountryin descending order. Then, the first3rows are selected. Suppose, thecountryfield in the last row isUSA. If the rows after them also containUSAin thecountryfield, those row...
WITH MEMBER [Date].[Calendar].[First8Months2003] AS Aggregate( PeriodsToDate( [Date].[Calendar].[Calendar Year], [Date].[Calendar].[Month].[August 2003] ) ) SELECT [Date].[Calendar].[First8Months2003] ON COLUMNS, [Product].[Category].Children ON ROWS FROM [Adventure Works] WHERE [Mea...
{ FIRST | LAST } ]} [, ...] ] [ { [ LIMIT { count | ALL } ] [ OFFSET start [ ROW | ROWS ] ] } | { LIMIT start, { count | ALL } } ] [ FETCH { FIRST | NEXT } [ count ] { ROW | ROWS } ONLY ] [ {FOR { UPDATE | SHARE } [ OF table_name [, ...] ] [...
WHERE FNumber NOT IN (SELECT FNumber FROM T_Employee ORDER BY FSalary DESC FETCH FIRST 5 ROWS ONLY )ORDER BY FSalary DESC FETCH FIRST 3 ROWS ONLY 抑制数据重复 DISTINCT DISTINCT关键字是用来进行重复数据抑制的最简单的功能，而且所有的数据库系统都支持DISTINCT，DISTINCT的使用也非常简单，...