oracle中的连接可分为,内连接(inner join)、外连接(outer join)、全连接(full join),不光是Oracle,其他很多的数据库也都有这3种连接查询方式 一、内连接inner join,这是我们经常用的查询方式,比如select * from A inner join B on A.field1=B.field2,个人认为,这样的内连接查询与下面的查询等效,select *...
Introduction to Oracle FULL OUTER JOIN clause# Suppose you have two tables T1 and T2. The following illustrates the full outer join of the two tables: SELECTselect_listFROMT1FULLOUTERJOINT2ONjoin_condition;Code language:SQL (Structured Query Language)(sql) ...
Similar to other joins, such asINNER JOIN,LEFT JOIN, you can use theUSINGoption to specify which column to test for equality when joining tables. The following illustrates the syntax of theRIGHT OUTER JOINwith theUSINGclause: SELECTcolumn_listFROMXRIGHTJOINYUSING(id);Code language:SQL (Structure...
Examples SELECT * FROM COUNTRIES JOIN CITIES USING (COUNTRY); SELECT * FROM COUNTRIES JOIN CITIES USING (COUNTRY, COUNTRY_ISO_CODE); SELECT * FROM oe.order_items oi JOIN oe.orders o USING(order_id); select t.* from hr.employees t, hr.departments d where t.department_id = d.department...
-- Perform a right outer join where the department number in the employee master table matches the department number in the department master table WHERE e.dept_no(+) = d.dept_no; Explanation: This SQL query performs a right outer join between the emp_mast (employee master) table and the...
Intersect Union Minus SQL Commands The correct commands for the scenarios are: INTERSECT:Find out which employee has updated at least one record in the PRODUCT table and added at least one record in the PET_CARE_LOG table. UNION:Find out which customers have purchased a dog in one sale and...
SQLFetch()fetches the first record from the result set generated by the stored procedure. The following examples illustrate how to call the above MS SQL Server/Sybasestored procedure with result sets/dynasets in Visual Basic using DAO and RDO on top of ODBC. This code works for Oracle8ipackag...
OUTER JOIN Syntax FETCH Clause DECLARE CURSOR Statement FOR UPDATE Option EXEC SQL Statement In all programs you replace the dollar ($) sign preceding the SQL sign with EXEC SQL and replace all the dollar signs before host variables with a colon (:). The following table compares the dollar ...
The Oracle specific PL/SQL code generated for functions, procedures, packages and triggers has to be reviewed to match the PostgreSQL syntax. You will find some useful recommendations on porting Oracle PL/SQL code to PostgreSQL PL/PGSQL at "Converting from other Databases to PostgreSQL", section...
关系数据库管理系统软件都支持SQL语言,可以通过SQL命令来实现各种数据操作功能。制,对数据库运行情况进行监控和报告等。通常,数据库系统的规模越大,这类功能就越强。可以利用数据字典功能为数据库中的表设置相应的属性和创建表之间的永久关系等。—27—1.1数据库基本知识...