SQL编写常见错误记录

mysql错误：1093 You can't specify target table for update in FROM clause

错误代码

UPDATE tb_applicant 
SET data_3 = 0
WHERE
	id IN (
		SELECT
			id
		FROM
			 tb_applicant 
		WHERE
			`status` = 1
		AND check_status = 1
		AND id NOT IN (
			SELECT
				applicant_id
			FROM
				tb_test_paper 
		)
	)

缘由：MySQL对子查询支持比较薄弱，能够创建缓存表解决，参考博客

更正后的代码

UPDATE tb_applicant 
SET data_3 = 0
WHERE
	id IN (
		SELECT
			temp.id
		FROM
			(select id from tb_applicant 
		WHERE
			`status` = 1
		AND check_status = 1
		AND id NOT IN (
			SELECT
				applicant_id
			FROM
				tb_test_paper 
		)) temp
	)