diff --git "a/\344\275\234\344\270\232 (2).sql" "b/\344\275\234\344\270\232 (2).sql"
new file mode 100644
index 0000000000000000000000000000000000000000..fa5de67190f39f94c20c05b3007b866b80b5871c
--- /dev/null
+++ "b/\344\275\234\344\270\232 (2).sql"	
@@ -0,0 +1,72 @@
+-- 字节长度
+select name,length(name) from user;
+select length('亚索'),OCTET_LENGTH('亚索')
+SELECT CHARACTER_LENGTH('亚索')
+
+-- 替换
+select replace('123456789','4','abc')
+select insert('123456789',2,3,'qwe')
+
+-- 截取
+SELECT left('123456789',3)
+SELECT RIGHT('123456789',3)
+SELECT SUBSTRING('123456789',-5,3)
+
+-- 拼接
+SELECT CONCAT('abc','ert','3456')
+
+
+-- 逆序
+select REVERSE('123456789')
+
+-- 大小写转换
+SELECT UPPER('日本qweRTY234')
+SELECT LOWER('日本qweRTY234')
+
+-- 去空格
+SELECT TRIM('    34  5       ');
+SELECT LTRIM('    67   6      ');
+SELECT RTRIM('     65    2     ');
+SELECT `REPLACE`('      12 3         ',' ','');
+
+-- 时间函数
+SELECT NOW()
+SELECT * FROM products
+INSERT INTO products(mytime,mydatetime,mydate,myyear,mytimestamp)
+values(now(),NOW(),NOW(),NOW(),NOW())
+SELECT UNIX_TIMESTAMP('2078-12-4 16:9:09');
+SELECT FROM_UNIXTIME(1921625244);
+-- 流程控制
+-- if 三目运算符
+select *,IF(money>=0,'正常'，'异常')资金状态 FROM USER;
+SELECT *
+(
+CASE
+WHEN money>=0 THEN
+'正常'
+ELSE
+'异常'
+END
+)资金状态
+from USER;
+-- 1在线 2离线 3限制登入 4被删除
+select *
+(
+CASE STATUS
+WHEN 1 THEN
+'在线'
+WHEN 2 THEN
+'离线'
+WHEN 3 THEN
+'限制登入'
+WHEN 4 THEN
+'被删除'
+ELSE
+'未知状态'
+END
+)用户状态
+from USER;
+SELECT * IFNULL(idcode,0)idcode FROM USER;
+
+
+