MySQL資料型別數值型之整數型之tinyint
1.1 tinyint說明
型別
長度
不指定時長度為
佔用位元組
範圍
有符號
無符號
tinyint
3
4
1(8bit)
-128~127
-128~127
0~255
id tinyint(M) [UNSIGNED] [ZEROFILL]
欄位名 欄位型別(長度) [無符號] [前導填充]
unsigned：
01：tinyint(M)後面加上unsigned後,就是無符號（tinyint的範圍就是0~255）
02：tinyint(M)後面不加上unsigned,就是有符號（tinyint的範圍就是-128~127）
zerofill：
01：進行前導零填充
02：tinyint(M)加上zerofile後，同時也會把unsigned引數也帶上(tinyint範圍0~255)
1.2 實踐檢驗
##建立chenliang庫
mysql> create database if not exists chenliang;
Query OK, 1 row affected (0.03 sec)
mysql> show databases like "chenliang";
+----------------------+
| Database (chenliang) |
+----------------------+
| chenliang |
+----------------------+
1 row in set (0.03 sec)
##進入chenliang庫
mysql> use chenliang;
Database changed
mysql> select database();
+------------+
| database() |
+------------+
| chenliang |
+------------+
1 row in set (0.01 sec)
測試一：測試欄位加上UNSIGNED後情況下插入資料的情況
##建立test1測試表（這裡指定了UNSIGNED，也就是無符號）
mysql> CREATE TABLE IF NOT EXISTS test1(
-> id tinyint(3) UNSIGNED
-> );
Query OK, 0 rows affected (0.06 sec)
mysql> desc test1;
+-------+----------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+----------------------+------+-----+---------+-------+
| id | tinyint(3) unsigned | YES | | NULL | |
+-------+----------------------+------+-----+---------+-------+
1 row in set (0.03 sec)
****測試01：測試插入範圍0~255的整數和走近255的整數
mysql> INSERT INTO test1 values(0); <==插入數值0，正常（沒有超過範圍）
Query OK, 1 row affected (0.06 sec)
mysql> INSERT INTO test1 values(255); <==插入數值255，正常（沒有超過範圍）
Query OK, 1 row affected (0.05 sec)
mysql> INSERT INTO test1 values(256); <=插入數值256,錯誤(超過了tinyint的範圍)
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> select * from test1;
+------+
| id |
+------+
| 0 |
| 255 |
+------+
2 rows in set (0.00 sec)
***測試02：測試-128~127範圍的資料是否能夠正常插入
mysql> INSERT INTO test1 values(-1); <==插入負數，報錯
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> INSERT INTO test1 values(-128); <==插入-128,報錯
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> INSERT INTO test1 values(-129); <==插入-129,報錯
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> select * from test1;
+-------+
| id |
+-------+
| 0 |
| 255 |
+-------+
2 rows in set (0.00 sec)
測試二：測試欄位加ZEROFILL上後情況下插入資料的情況
##建立test2表，（這裡指定了zerofill,也就是前導零填充）
mysql> CREATE TABLE IF NOT EXISTS test2(
-> id tinyint(3) ZEROFILL
-> );
Query OK, 0 rows affected (0.07 sec)
mysql> desc test2;
+-------+------------------------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+------------------------------+------+-----+---------+-------+
| id | tinyint(3) unsigned zerofill | YES | | NULL | |
+-------+------------------------------+------+-----+---------+-------+
1 row in set (0.00 sec)
^只指定unsigned，不會有zerofill
^只指定zerofill時，會帶上unsigned
****測試01：測試插入範圍0~255的整數和走近255的整數
mysql> INSERT INTO test2 values(0);
Query OK, 1 row affected (0.01 sec)
mysql> INSERT INTO test2 values(255);
Query OK, 1 row affected (0.08 sec)
mysql> INSERT INTO test2 values(256);
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> select * from test2;
+------+
| id |
+------+
| 000 |
| 255 |
+------+
2 rows in set (0.00 sec)
***測試02：測試-128~127範圍的資料是否能夠正常插入
mysql> INSERT INTO test2 values(-1);
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> INSERT INTO test2 values(-128);
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> INSERT INTO test2 values(-129);
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> select * from test2;
+------+
| id |
+------+
| 000 |
| 255 |
+------+
2 rows in set (0.00 sec)
測試一：測試欄位不加unsigned 和ZEROFILL上後情況下插入資料的情況
##建立test3表（不加unsigned和zerofill）
mysql> CREATE TABLE test3(
-> id tinyint(3)
-> );
Query OK, 0 rows affected (0.06 sec)
mysql> desc test3;
+-------+------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+-------+------------+------+-----+---------+-------+
| id | tinyint(3) | YES | | NULL | |
+-------+------------+------+-----+---------+-------+
1 row in set (0.01 sec)
****測試01：測試插入整數
mysql> INSERT INTO test3 values(0);
Query OK, 1 row affected (0.05 sec)
mysql> INSERT INTO test3 values(128);
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> select * from test3;
+------+
| id |
+------+
| 0 |
+------+
1 row in set (0.01 sec)
***測試02：測試插入負數
mysql> INSERT INTO test3 values(-1);
Query OK, 1 row affected (0.10 sec)
mysql> INSERT INTO test3 values(-128);
Query OK, 1 row affected (0.02 sec)
mysql> INSERT INTO test3 values(-129);
ERROR 1264 (22003): Out of range value for column 'id' at row 1
mysql> select * from test3;
+------+
| id |
+------+
| 0 |
| -1 |
| -128 |
+------+
3 rows in set (0.00 sec)
1.3 tinyint總結
格式：
id tinyint(M) [UNSIGNED] [ZEROFILL]
欄位名 欄位型別(長度) [無符號] [前導填充]
unsigned：
01：tinyint(M)後面加上unsigned後,就是無符號（tinyint的範圍就是0~255）
02：tinyint(M)後面不加上unsigned,就是有符號（tinyint的範圍就是-128~127）
zerofill：
01：進行前導零填充（插入數值1，表中顯示的是001，因為tinyint的長度為3）
02：tinyint(M)加上zerofile後，同時也會把unsigned引數也帶上(tinyint範圍0~255)