记录值是否存在另一个表中

November 10, 2020

https://stackoverflow.com/questions/2686254/how-to-select-all-records-from-one-table-that-do-not-exist-in-another-table

最简单且性能最高的方案为:

SELECT t1.name
FROM table1 t1
LEFT JOIN table2 t2 ON t2.name = t1.name
WHERE t2.name IS NULL

常规的方式为:

SELECT name
FROM table2
WHERE name NOT IN
    (SELECT name 
     FROM table1)