为什么MySQL在FULL OUTER JOIN上报告语法错误？
SELECT airline, airports.icao_code, continent, country, province, city, website
FROM airlines FULL OUTER JOIN airports ON airlines.iaco_code = airports.iaco_code FULL OUTER JOIN cities ON airports.city_id = cities.city_id FULL OUTER JOIN provinces ON cities.province_id = provinces.province_id FULL OUTER JOIN countries ON cities.country_id = countries.country_id FULL OUTER JOIN continents ON countries.continent_id = continents.continent_id 它说
您的SQL语法有误；检查与您的MySQL服务器版本相对应的手册以获取正确的语法，以airports在第4行的“ airlines.iaco_code = airport.iaco_code完全外部联接”附近使用
语法对我来说似乎正确。我以前从未做过很多联接，但是我需要一个表中的那些列，这些列被各种ID交叉引用。
写回答
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FULL OUTER JOINMySQL中没有。见7.2.12。外连接简化和12.2.8.1。JOIN语法：
您可以FULL OUTER JOIN使用UNION（从MySQL 4.0.0开始）进行仿真：
有两个表t1，t2：
SELECT * FROM t1 LEFT JOIN t2 ON t1.id = t2.id UNION SELECT * FROM t1 RIGHT JOIN t2 ON t1.id = t2.id 有三个表t1，t2，t3：
SELECT * FROM t1 LEFT JOIN t2 ON t1.id = t2.id LEFT JOIN t3 ON t2.id = t3.id UNION SELECT * FROM t1 RIGHT JOIN t2 ON t1.id = t2.id LEFT JOIN t3 ON t2.id = t3.id UNION SELECT * FROM t1 RIGHT JOIN t2 ON t1.id = t2.id RIGHT JOIN t3 ON t2.id = t3.id 来源：stack overflow
2020-05-13 13:57:56赞同 展开评论 打赏
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