UPDATE pay_method_basic_info ft INNER JOIN ( 	SELECT 		channel_id, 		method_id, 	IF 		( @channelId = t.channel_id, @row_num := @row_num + 1, @row_num := 1 ) AS row_num, 		@channelId := t.channel_id  	FROM 		pay_method_basic_info t  	) mt ON ft.channel_id = mt.channel_id  	AND ft.method_id = mt.method_id  	SET ft.method_id = ft.channel_id * 100 + row_num
原文:https://www.cnblogs.com/Asuphy/p/14332393.html