2.具体分析 Oracle在9i中引入了with语句。with语句用来给查询语句中的子查询命名,随后就可以在查询语句的其他地方引用这个名称。 格式如下: WITH <alias_name> AS (subquery_ sql statement) SELECT <column_name_list> FROM <alias>; 3.解决方案 WITH TMP_TABAS (SELECTA.ORGCODE, (SELECTT.ORGNAMEFROMYLT_O...
WITH <alias_name> AS (subquery_sql_statement) SELECT <column_name_list> FROM <alias>; 注意,定义了WITH语句必须在后边的查询中使用,否则提示错误。 WITH子句相关总结: 1、在同级select前有多个查询定义的时候,第1个用with,后面的不用with,并且用逗号隔开。 2、最后一个with 子句与下面的查询之间不能有逗...
With语句的语法(AS后面的括号是不可以空缺的) 1WITH<alias_name>AS(subquery_sql_statement) 2SELECT<column_name_list>FROM<alias>; 简单的with语句: WITHAAS (SELECT*FROMDUAL) SELECT*FROMA 注意,定义了WITH语句必须在后边的查询中使用,否则提示错误信息: 1WITHAAS 2(SELECT*FROMDUAL) 3SELECT*FROMdual (错...
Oracle在9i中引入了with语句。with语句用来给查询语句中的子查询命名,随后就可以在查询语句的其他地方引用这个名称。 格式如下: WITH <alias_name> AS (subquery_ sql statement) SELECT <column_name_list> FROM <alias>; 3.解决方案 WITHTMP_TABAS(SELECTA.ORGCODE,(SELECTT.ORGNAMEFROMYLT_ORG_INFO TWHERET...
oracle with as 用法 WITH subquery_name AS (the aggregation SQL statement) SELECT (query naming subquery_name); Retuning to our oversimplified example, let’s replace the temporary tables with the SQL “WITH” clause”: === 下面自己小试一把,当然,一点都不复杂,很简单很简单的例子,呵呵。 view...
The SQL-99 “WITH clause” is very confusing at first because the SQL statement does not begin with the word SELECT. Instead, we use the “WITH clause” to start our SQL query, defining the aggregations, which can then be named in the main query as if they were “real” tables: ...
1、with table as 相当于建个临时表(用于一个语句中某些中间结果放在临时表空间的SQL语句),Oracle 9i 新增WITH语法,可以将查询中的子查询命名,放到SELECT语句的最前面。 语法就是 with tempname as (select ...) select ... 例子: with t as (select * from emp where depno=10) select...
ORACLE_WITH_AS_用法大全 ORACLE WITH AS 用法 有两张表，分别为A、B，求得一个字段的值先在表A中寻找，如果A表中存在数据，则输出A表的值；如果A表中不存在，则在B表中寻找，若B表中有相应记录，则输出B表的值；如果B表中也不存在，则输出"no records”字符串。view plaincopy to clipboardprint?1....
The SQL-99 “WITH clause” is very confusing at first because the SQL statement does not begin with the word SELECT. Instead, we use the “WITH clause” to start our SQL query, defining the aggregations, which can then be named in the main query as if they were “real” tables: WIT...
1 语法：WITHsubquery_nameAS(the aggregation SQL statement)SELECT(query naming subquery_name);2 创建测试表tbl1、tbl2，往tbl1里插入2条数据，往tbl2里插入1000000条数据 3 此时我们单看一下全表扫描tbl2时的情况。通过下图，我们看到单对tbl2全表扫描时的逻辑读为6911 4 下面我们构造一个相关子查询，看看...