Question

我有两个表（Test和Prod）并且有一个存储过程，每天运行以在Prod中不存在的Test中插入行。

目前它只是一个简单的插入，如下所示：

INSERT INTO Table1 ('Field1','Field2','Field3','Field4')
SELECT 'Field1','Field2','Field3','Field4' 
FROM Table2
WHERE Table2.Field1 NOT IN (SELECT Table1.Field1 FROM Table1)

问题是这些表有很多行，这需要很长时间才能运行。是否有更好/更有效的方式来写这个？

Answer 1

在两个表上的Field1上创建索引。除此之外，我不知道如何优化它。

Answer 2

您可以尝试这样的事情：

INSERT INTO Table1 (Field1, Field2, Field3, Field4)
SELECT t2.Field1, t2.Field2, t2.Field3, t2.Field4 
FROM Table2 t2
LEFT JOIN Table1 t1 ON (t1.Field1 = t2.Field1)
WHERE t1.Field1 IS NULL;

Answer 3

INSERT INTO Table1 ('Field1','Field2','Field3','Field4')
SELECT 'Field1','Field2','Field3','Field4' 
FROM Table2 t2
WHERE NOT EXISTS (SELECT t1.Field1 FROM Table1 t1 WHERE t1.Field1 = t2.Field1)

优化大型插入语句

3 个答案: