mysql 查詢一個表中有的記錄且在另一個表中無相關的記錄sql

1、

SELECT
	*
FROM
	table1
WHERE
	xxx
and fieldsname not in (
	SELECT fieldsname from table2 where xxxx)
);

2、

SELECT
	a.*
FROM
	table1 a
LEFT JOIN table2 b ON (a.fieldsname = b.fieldsname)
WHERE
	xxx
AND b.fieldsname IS NULL;

3、

SELECT
	a.*
FROM
	table1 a
WHERE
	xxx
and 
	NOT EXISTS (
		SELECT
			1
		FROM
			table2 b
		WHERE
			a.fieldsname = b.fieldsname
	);