1. Oracle的sql基本语法--查询 (1)DISTINCT语法结构 --SELECTDISTINCT列1,列2,列3...from 表名;select distinct stuaddress,grade from jalen.stuinfo;select distinct job from scott.emp; 1. 2. 3. ##(2)where的 =、IN、LIKE、BETWEEN...AND、AND、OR、NOT --where的=、IN、LIKE、BETWEEN...AND、...
如果只想为每列显示不同的值,则需要单独考虑每列,并可以使用如下内容: SELECT c1.col001, c2.col002 FROM ( SELECT DISTINCT col001, DENSE_RANK() OVER (ORDER BY col001) AS rnk FROM table_name ) c1 FULL OUTER JOIN ( SELECT DISTINCT col002, DENSE_RANK() OVER (ORDER BY col002) AS rnk FR...
select {[distinct]列名。列名,…}from表名[where条件] [group by分组列名] [having聚合函数] [order by排序列名ASC| DESC] 当中keyworddistinct表示去除部分列中反复数据, 仅仅是在查询的时候去除,而该表内部数据纹丝不动 二、查询指定的列 假设想查询某一个或是多个指定列。能够编写相似于以下的SQL语句。 例1...
Pivot SQL tables with CASE or FILTER. Turn rows into columns for the entity-attribute-value model (EAV).
A subquery isused only in conjunction with the XML keyword. When you specify asubquery, all values found by the subquery are used for pivoting. The output isnot the same cross-tabular format returned by non-XML pivot queries. Instead ofmultiple columns specified in the pivot_in_clause, the...
aggregate_function([DISTINCT | ALL]expression) The syntax elements are: aggregate_function Gives the name of the function—e.g., SUM, COUNT, AVG, MAX, MIN DISTINCT Specifiesthat the aggregate function should consider only distinct values of the argument expression. ...
You can specify multiple columns in a GROUP BY clause. For example, the following query includes the city and description columns from the employee table in a GROUP BY clause: SQL> -- create demo table SQL> create table Employee( 2 ID VARCHAR2(4 BYTE) NOT NULL, 3 First_Name VARCHAR2(...
数据库面试题(SQL+ORACLE) 数据库基础(面试常见题) 一、数据库基础 1. 数据抽象:物理抽象、概念抽象、视图级抽象,内模式、模式、外模式 2. SQL语言包括数据定义、数据操纵(Data Manipulation),数据控制(Data Control) 数据定义:Create Table,Alter Table,Drop Table, Craete/Drop Index等...
Oracle allows multiple BLOB and CLOB columns per table. BLOBS and CLOBS may or may not be stored in the row depending on their size. If the Microsoft SQL Server TEXT column is such that the data never exceeds 4000 bytes, convert the column to an Oracle VARCHAR2 data type column instead...
SELECT DISTINCT TABLE_NAME FROM ALL_TAB_COLUMNS WHERE OWNER = 'PORTAL' -- 待同步模式的模式名 AND DATA_TYPE IN ( 'BLOB' , 'TINYBLOB' , 'MEDIUMBLOB' , 'LONGBLOB' , 'CLOB' , 'NCLOB' , 'XML' , 'RAW' , 'LONG RAW' , 'LONG' , 'BFILE' , 'BINARY' , 'VARBINARY' , 'LONGVARBIN...