两个结果集都被追加到从函数返回的单个集合中。当然，行类型必须匹配。参见RETURN QUERY的手册。
/* Process RETURNING if present */ /* ... */ return result; } COPY 的核心执行逻辑位于 CopyFrom 函数中,与 ExecInsert 函数较大的区别是其会在内存中维护一段 TupleTableSlot 数组,对于输入的数据行会先通过 CopyMultiInsertInfoStore 在内存中缓存:...
set_base_rel_pathlists函数的目的是为每一个base rel找出所有可用的访问路径(包括顺序扫描和所有可用的索引),每一个可用的路径都会添加到pathlist链表中。这一小节主要介绍常规(区别于并行)顺序扫描部分。 make_one_rel源代码: RelOptInfo * make_one_rel(PlannerInfo *root,List*joinlist) {//.../* * Com...
The INSERT statement can be used to insert a single row, multiple rows, or data from another table. It can also handle default values and conditional inserts. Basic INSERT StatementThis example demonstrates how to insert a single row into the books table: basic_insert.sql ...
CREATE TABLE inventory( id INT PRIMARY KEY, name VARCHAR(255) NOT NULL, price DECIMAL(10,2) NOT NULL, quantity INT NOT NULL ); INSERT INTO inventory(id, name, price, quantity) VALUES (1, 'A', 15.99, 100), (2, 'B', 25.49, 50), (3, 'C', 19.95, 75) RETURNING *; Outpu...
The PostgreSQL UPDATE statement is used to modify existing rows in a table. It allows you to change the values of one or more columns in one or more rows. This tutorial covers how to use the UPDATE statement with practical examples. ...
3.5. Returning Cursors PL/pgSQL functions can return cursors to the caller. This is useful to return multiple rows or columns, especially with very large result sets. To do this, the function opens the cursor and returns the cursor name to the caller (or simply opens the cursor using a ...
* ecxt_aggnulls arrays, which hold the computed agg values for the current * input group during evaluation of an Agg node's output tuple(s). We * create a second ExprContext, tmpcontext, in which to evaluate input * expressions and run the aggregate transition functions. ...
* and is not used when returning base data types. It is only needed if * you intend to use BuildTupleFromCStrings() to create the return tuple.*/AttInMetadata*attinmeta;/** memory context used for structures that must live for multiple calls ...
2) Inserting multiple rows and returning inserted rows The following statement uses the INSERT statement to insert two rows into the contacts table and returns the inserted rows: INSERT INTO contacts (first_name, last_name, email) VALUES ('Alice', 'Johnson', 'alice.johnson@example.com'), (...