摘要：统计重复数据出现次数 SELECT * FROM ( SELECT * FROM ( SELECT count(t1.compare_id) AS c1,t1.* FROM t1 LEFT JOIN t3 ON t1.compare_id=t3.compare_id WHERE t1.compare 阅读全文

摘要：简单比较 1、SELECT * FROM t2 WHERE id NOT IN (SELECT id FROM t1); 2、SELECT * FROM t2 WHERE NOT EXISTS(SELECT * FROM t1 WHERE t1.id=t2.id); 3、SELECT t2.* FR 阅读全文

摘要：$arr = [ ['is_reg' => 0, 'role' => 1, 'bk' => 1], ['is_reg' => 1, 'role' => 2, 'bk' => 2], ['is_reg' => 1, 'role&# 阅读全文