mysql常见数据类型 - 自律即自由

  1 #常见的数据类型
  2 
 17 
 18 #一、整型
 19 
 31 
 32 #1.如何设置无符号和有符号
 33 
 34 DROP TABLE IF EXISTS tab_int;
 35 CREATE TABLE tab_int(
 36     t1 INT(7) ZEROFILL,
 37     t2 INT(7) ZEROFILL 
 38 
 39 );
 40 
 41 DESC tab_int;
 42 
 43 
 44 INSERT INTO tab_int VALUES(-123456);
 45 INSERT INTO tab_int VALUES(-123456,-123456);
 46 INSERT INTO tab_int VALUES(2147483648,4294967296);
 47 
 48 INSERT INTO tab_int VALUES(123,123);
 49 
 50 
 51 SELECT * FROM tab_int;
 52 
 53 
 54 #二、小数
 55 
 80 #测试M和D
 81 
 82 DROP TABLE tab_float;
 83 CREATE TABLE tab_float(
 84     f1 FLOAT,
 85     f2 DOUBLE,
 86     f3 DECIMAL
 87 );
 88 SELECT * FROM tab_float;
 89 DESC tab_float;
 90 
 91 INSERT INTO tab_float VALUES(123.4523,123.4523,123.4523);
 92 INSERT INTO tab_float VALUES(123.456,123.456,123.456);
 93 INSERT INTO tab_float VALUES(123.4,123.4,123.4);
 94 INSERT INTO tab_float VALUES(1523.4,1523.4,1523.4);
 95 
 96 
 97 
 98 #原则：
 99 
103 
104 #三、字符型
105 
131 
132 
133 
134 CREATE TABLE tab_char(
135     c1 ENUM("a","b","c")
136 
137 
138 );
139 
140 
141 INSERT INTO tab_char VALUES("a");
142 INSERT INTO tab_char VALUES("b");
143 INSERT INTO tab_char VALUES("c");
144 INSERT INTO tab_char VALUES("m");
145 INSERT INTO tab_char VALUES("A");
146 
147 SELECT * FROM tab_set;
148 
149 
150 
151 CREATE TABLE tab_set(
152 
153     s1 SET("a","b","c","d")
154 
155 
156 
157 );
158 INSERT INTO tab_set VALUES("a");
159 INSERT INTO tab_set VALUES("A,B");
160 INSERT INTO tab_set VALUES("a,c,d");
161 
162 
163 #四、日期型
164 
165 
183 
184 
185 CREATE TABLE tab_date(
186     t1 DATETIME,
187     t2 TIMESTAMP
188 
189 );
190 
191 
192 
193 INSERT INTO tab_date VALUES(NOW(),NOW());
194 
195 SELECT * FROM tab_date;
196 
197 
198 SHOW VARIABLES LIKE "time_zone";
199 
200 SET time_zone="+9:00";