sql - 删除其他表中不存在的记录

Question

我有 2 个表：Table1 (ID, Table2ID, Col1,....) 和 Table2 (ID, Col1,....)。Table2ID 是来自 Table2 的外键引用。我想编写一个查询以从 Table2 中删除 ID（Table2ID）在 Table1 中不存在的记录。表 1 > 3 亿和表 1 > 1 亿的记录数。我有两个查询，但不确定哪一个会更快：

查询 1（无效）：

delete from Table2
select ID from Table2
except
select Table2ID from Table1

查询 2：

delete from Table2
where ID not in (select distinct Table2ID from Table1)

Answer 1

尝试这个...

select * 
into #temptable2
from table2 t2,table1 t1 
where t1.table2id = t2.id;

truncate table table2;

insert into table2
select * from #temptable2;    

Answer 2

Query2 更快

delete from Table2
where ID not in (select distinct Table2ID from Table1)

Answer 3

这会更快：

DELETE B
FROM table1 a
LEFT OUTER JOIN table2 b ON a.table2id = b.id 
WHERE b.id IS null