SELECTDISTINCTcolumn1,column2,...FROMtable_name; 其中,column1,column2,等是您要选择不同值的列名称,而table_name是您从中选择不同值的表的名称。 以下是一些示例: 从"Customers"表中选择不同的国家: 代码语言:sql AI代码解释 SELECTDISTINCTCountryFROMCustomers; 这将返回"Customers"表中不同国家的列表。 计...
SQL SELECT DISTINCT 语句 SELECT DISTINCT 语句用于返回唯一不同的值。 在表中,一个列可能会包含多个重复值,有时您也许希望仅仅列出不同(distinct)的值。 DISTINCT 关键词用于返回唯一不同的值。P1 SQL SELECT DISTINCT 语法 参数说明: column1, column2, ...:要选择的字段名称,可以为多个字段。如果不指定字段...
Note:This command cannot be used to list all employees in Norway and USA. In the example above we have two employees with equal names, and only one of them is listed. The UNION command only selects distinct values. UNION ALL The UNION ALL command is equal to the UNION command, except ...
SELECT DISTINCT agent_code, ord_amount, cust_code, ord_num: This line specifies that you want to retrieve unique combinations of 'agent_code', 'ord_amount', 'cust_code', and 'ord_num'. The DISTINCT keyword ensures that only unique combinations are returned; any duplicate combinations will ...
1>.查看SELECT命令的帮助信息 mysql>?SELECTName:'SELECT'Description: Syntax:SELECT[ALL | DISTINCT | DISTINCTROW][HIGH_PRIORITY][STRAIGHT_JOIN][SQL_SMALL_RESULT][SQL_BIG_RESULT][SQL_BUFFER_RESULT]SQL_NO_CACHE[SQL_CALC_FOUND_ROWS]select_expr[, select_expr ...][FROM table_references ...
SELECT DISTINCT often your results will include many duplicate values. If you want to select all the unique values from a column, you can use the DISTINCT keyword. SELECT DISTINCT language FROM films; Learning to COUNT 统计“记录” What if you want to count the number of employees in your ...
SELECT COUNT(DISTINCT Customer) AS NumberOfCustomers FROM Orders 执行上述SQL后，结果集将显示出 'Orders' 表中有多少不同的客户，如所示：NumberOfCustomers: 3 这些客户包括Bush, Carter 和 Adams。在 SQL 中，如果你想获取特定字段（如 'OrderPrice'）的第一个记录值，可以使用 FIRST() 函数。
全新動態管理檢視sys.dm_db_column_store_row_group_physical_stats (Transact-SQL)提供資料列群組層級的效能疑難排解資訊。 數據行存放區索引上的所有查詢都可以在批次模式中執行。 先前,只有平行查詢可以在批次模式中執行。 Sort、Distinct Sort和Distinct運算符會以批次模式執行。
The image below shows the output from SELECT statement. Now that we have a simple test table, we can start talking about the SQL SELECT DISTINCT clause. Distinct with Column Combinations In its simplest form, the DISTINCT clause returns a distinct list of values from one or more columns. Bel...
触发条件:DISTINCT和GROUP BY不能出现在同一个SELECT子句中。 处理方法:修改语句,不要同时使用DISTINCT和GROUP BY。 ODPS-0130071:Semantic analysis exception - Cannot insert into target table because column number/types are different 模块:PARSER。