PostgreSQL数据库日常学习笔记8-NOT,LIKE
发布时间:2020-12-13 16:47:09 所属栏目:百科 来源:网络整理
导读:先学习NOT(逻辑非)用法。 #查询StudentBirthday非空列SELECT * FROM "public"."Students" WHERE "StudentBirthday" IS NOT NULL;#注意对比两个语句查询结果SELECT "StudentBirthday" FROM "public"."Students" WHERE "StudentBirthday" IS NOT NULL; 排除
先学习NOT(逻辑非)用法。 #查询StudentBirthday非空列 SELECT * FROM "public"."Students" WHERE "StudentBirthday" IS NOT NULL; #注意对比两个语句查询结果 SELECT "StudentBirthday" FROM "public"."Students" WHERE "StudentBirthday" IS NOT NULL; 排除非条件值 #不查询StudentSalary=2值 SELECT * FROM "public"."Students" WHERE "StudentSalary" NOT IN('2'); #对比查询语句 SELECT "StudentName","StudentAddress" FROM "public"."Students" WHERE "StudentSalary" NOT IN('2'); LIKE支持模糊查询,LIKE与两个通配符(%与_)一起使用,百分号表示零个,一个或多个字符。下划线代表一个单一字符。通配符可以被组合使用。ILIKE和LIKE 类似,LIKE区分大小写,ILIKE不区分。SIMILAR TO和LIKE有相似性,不过后者支持模糊查询同时还支持正则表达式。 先插入两条数据用于练习。 INSERT INTO "Students" VALUES (13,'杜牧','0803-1-1','陕西省西安市',3); INSERT INTO "Students" VALUES (14,'李商隐','0817-1-1',NULL,NULL); #查询所有杜姓人名,匹配单个字符 SELECT * FROM "public"."Students" WHERE "StudentName" LIKE '杜_'; #匹配多个字符,本例匹配StudentAddress列中含有陕西查询结果 SELECT "StudentName","StudentAddress" FROM "public"."Students" WHERE "StudentAddress" LIKE '%陕西%'; (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |