CROSS JOIN（交叉连接）
适用于 ✅ 开源版 ✅ 专业版 ✅ 企业版
CROSS JOIN 创建它所连接的两个表之间的笛卡尔积或交叉积。它不允许指定任何连接谓词。
当一个集合的每个元素需要与另一个集合的每个元素组合时，它是一个在报告中偶尔有用的运算符。例如，当您想要生成一个组合员工和工作日的报告，然后对结果表做一些事情时
SELECT EMPLOYEE.NAME, WEEKDAY.NAME FROM EMPLOYEE CROSS JOIN WEEKDAY
create.select(EMPLOYEE.NAME, WEEKDAY.NAME)
.from(EMPLOYEE)
.crossJoin(WEEKDAY)
.fetch();
一些示例输出可能是
+---------------+--------------+ | EMPLOYEE.NAME | WEEKDAY.NAME | +---------------+--------------+ | Jon | Monday | | Jon | Tuesday | | Jon | Wednesday | | Jon | Thursday | | Jon | Friday | | Jon | Saturday | | Jon | Sunday | | Jane | Monday | | Jane | Tuesday | | Jane | Wednesday | | Jane | Thursday | | Jane | Friday | | Jane | Saturday | | Jane | Sunday | | ... | ... | +---------------+--------------+
SELECT EMPLOYEE.NAME, WEEKDAY.NAME FROM EMPLOYEE, WEEKDAY
create.select(EMPLOYEE.NAME, WEEKDAY.NAME)
.from(EMPLOYEE, WEEKDAY)
.fetch();
select(BOOK.ID, AUTHOR.ID).from(BOOK.crossJoin(AUTHOR))
翻译成以下特定方言的表达式
ASE
SELECT BOOK.ID, AUTHOR.ID
FROM BOOK
JOIN AUTHOR
ON 1 = 1
Aurora MySQL, Aurora Postgres, BigQuery, ClickHouse, CockroachDB, DB2, Databricks, Derby, Exasol, Firebird, H2, HSQLDB, Hana, Informix, MariaDB, MemSQL, MySQL, Oracle, Postgres, Redshift, SQLDataWarehouse, SQLServer, SQLite, Snowflake, Sybase, Teradata, Trino, Vertica, YugabyteDB
SELECT BOOK.ID, AUTHOR.ID FROM BOOK CROSS JOIN AUTHOR
Access, DuckDB
/* UNSUPPORTED */
使用 jOOQ 3.21 生成。早期 jOOQ 版本的支持可能有所不同。 在我们的网站上翻译您自己的 SQL
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