SQL 型 V3.2.4 开发指南 SQL 语法 普通租户(Oracle 模式) SQL 语句 DML SELECT WITH CLAUSE 更新时间:2025-01-27 23:00:01 本节将介绍带有 WITH CLAUSE 子句的 SELECT。 描述 如果查询语句中有多个相同的子查询,可以把相同的子查询放在WITH CLAUSE中作为公共表达式,在主体查询中直接引用即可。
You can use the WITH clause in Oracle, SQL Server, or other databases to create a recursive query. As mentioned earlier in this article, it’s useful for data that is set up in a hierarchy. Oracle offers the CONNECT BY PRIOR syntax as an alternative to the WITH clause for recursive que...
We can also use the SQL-99 “WITH clause” instead of temporary tables. The Oracle SQL “WITH clause” will compute the aggregation once, give it a name, and allow us to reference it (maybe multiple times), later in the query. The SQL-99 “WITH clause” is very confusing at first b...
TheWITH query_name clause lets you assign a name to a subquery block. You can then reference the subquery block multiple places in the query by specifying the query name. Oracle optimizes the query by treating the query name as either an inline view or as a temporary table. (WITH语句只能...
ORACLE With查询语句不是以select开始的,而是以“WITH”关键字开头 可认为在真正进行查询之前预先构造了一个临时表,之后便可多次使用它做进一步的分析和处理 WITH Clause方法的优点 增加了SQL的易读性,如果构造了多个子查询,结构会更清晰;更重要的是:“一次分析,多次使用”,这也是为什么会提供性能的地方,达到了“少...
We can also use the SQL-99 "WITH clause" instead of temporary tables. The Oracle SQL "WITH clause" will compute the aggregation once, give it a name, and allow us to reference it (maybe multiple times), later in the query. The SQL-99 "WITH clause" is very confusing at first because...
To do this, ensure thesql_transpilerparameter ison(it'soffby default). When a function in thewhereclause is transpiled, you can see the case expression instead of the function in the predicate section of the plan: There are a few differences betweencasein PL/SQL andOracle SQL. ...
'VARCHAR' is not a recognized built-in function name. 'WHEN MATCHED' cannot appear more than once in a 'UPDATE' clause of a MERGE statement. "EXECUTE AT" with Dynamic Linked Server Name "explicit value must be specified for identity column in table" error in SQL 2000 "FROM clause have ...
FUNCTION with_function(p_id IN NUMBER) RETURN NUMBER IS BEGIN RETURN p_id; END; SELECT with_function(id) FROM test WHERE rownum = 1 / WITH_FUNCTION(ID) --- 1 SQL> 有意思的是,当WITH子句中包含PL/SQL声明时,分号";"不再能用作SQL语句的终止符。如果我们使用它,SQL*Plus会等待更多命令文本...
Oracle PL/SQL celebrates its 31st birthday in 2020. I know this because I am looking at the first Oracle PL/SQL user guide ever published; it is for PL/SQL Release 1.0, and its date of publication is September 1989. I worked for Oracle at that time, building the first sales automation...