Selecting Records in Parallel from Multiple Tables
mysql> mysql> CREATE TABLE prospect -> ( -> fname CHAR(40), -> lname CHAR(40), -> addr CHAR(40) -> ); Query OK, 0 rows affected (0.01 sec) mysql> mysql> CREATE TABLE customer -> ( -> last_name CHAR(40), -> first_name CHAR(40), -> address CHAR(40) -> ); Query OK, 0 rows affected (0.01 sec) mysql> mysql> CREATE TABLE vendor -> ( -> company CHAR(60), -> street CHAR(30) -> ); Query OK, 0 rows affected (0.01 sec) mysql> mysql> INSERT INTO prospect (fname, lname, addr) -> VALUES -> ('Peter','Jones','482 Main St., Apt. 402'), -> ('Bernice','Smith','916 Maple Dr.') -> ; Query OK, 2 rows affected (0.00 sec) Records: 2 Duplicates: 0 Warnings: 0 mysql> mysql> INSERT INTO customer (first_name, last_name, address) -> VALUES -> ('Grace','Peterson','16055 First Ave.'), -> ('Bernice','Smith','916 Maple Dr.'), -> ('Walter','Brown','8602 1st St.') -> ; Query OK, 3 rows affected (0.00 sec) Records: 3 Duplicates: 0 Warnings: 0 mysql> mysql> INSERT INTO vendor (company, street) -> VALUES -> ('Database, Inc.','38 Third Ave.'), -> ('Xml, Ltd.','213B Commerce Park.') -> ; Query OK, 2 rows affected (0.00 sec) Records: 2 Duplicates: 0 Warnings: 0 mysql> mysql> mysql> SELECT fname, lname, addr FROM prospect -> UNION -> SELECT first_name, last_name, address FROM customer -> UNION -> SELECT company, '', street FROM vendor; +----------------+----------+------------------------+ | fname | lname | addr | +----------------+----------+------------------------+ | Peter | Jones | 482 Main St., Apt. 402 | | Bernice | Smith | 916 Maple Dr. | | Grace | Peterson | 16055 First Ave. | | Walter | Brown | 8602 1st St. | | Database, Inc. | | 38 Third Ave. | | Xml, Ltd. | | 213B Commerce Park. | +----------------+----------+------------------------+ 6 rows in set (0.00 sec) mysql> mysql> drop table prospect; Query OK, 0 rows affected (0.00 sec) mysql> drop table customer; Query OK, 0 rows affected (0.00 sec) mysql> drop table vendor; Query OK, 0 rows affected (0.00 sec) mysql> mysql>