本文分享給大家的是MySQL學習筆記系列文章的入門篇，主要講述MySQL表的基本操作指令，非常詳細，有需要的小夥伴可以來查看下
#建立表
create table 表名
create table if not exists 表名
mysql> create database company; Query OK, 1 row affected (0.00 sec) mysql> use company; Database changed mysql> create table if not exists t_dept( -> deptno int, -> dname varchar(20), -> loc varchar(40)); Query OK, 0 rows affected (0.20 sec) mysql> show tables; +-------------------+ | Tables_in_company | +-------------------+ | t_dept | +-------------------+ 1 row in set (0.00 sec) mysql>
顯示目前庫下的所有表格<br/>
show tables;
<br/>
mysql> show tables; +-------------------+ | Tables_in_company | +-------------------+ | t_dept | +-------------------+ 1 row in set (0.00 sec)
檢視表的結構<br/>
describe 表名<br/>
#簡單寫<br/>
##desc 表名<br/>
##
mysql> describe t_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 3 rows in set (0.00 sec) mysql> desc t_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 3 rows in set (0.00 sec)
show create table 表名
<br/>
mysql> show create table t_dept;
+--------+--------------------------------------------------------------+
| Table | Create Table |
+--------+--------------------------------------------------------------+
| t_dept | CREATE TABLE `t_dept` (
`deptno` int(11) DEFAULT NULL,
`dname` varchar(20) DEFAULT NULL,
`loc` varchar(40) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8 |
+--------+--------------------------------------------------------------+
1 row in set (0.00 sec)
show create table t_dept \G
mysql> show create table t_dept \G
*************************** 1. row ***************************
Table: t_dept
Create Table: CREATE TABLE `t_dept` (
`deptno` int(11) DEFAULT NULL,
`dname` varchar(20) DEFAULT NULL,
`loc` varchar(40) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)<br/>drop table 表格名稱drop table if exists 表格名稱
<br/>
##mysql> drop table if exists t_dept; Query OK, 0 rows affected (0.12 sec) mysql> show tables; Empty set (0.00 sec)
修改表名<br/>
ALTER TABLE old_table_name RENAME [TO] new_table_name<br/><br/><br/>ALTER TABLE old_table_name RENAME [TO] new_table_name
old_table_name 原始表名new_table_name 新表名<br/>將t_dept修改為tab_dept
new_table_name 新表名將t_dept修改為tab_dept<br/> <br/>#
mysql> alter table t_dept rename tab_dept; Query OK, 0 rows affected (0.09 sec) mysql> show tables; +-------------------+ | Tables_in_company | +-------------------+ | tab_dept | +-------------------+ 1 row in set (0.00 sec) mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 3 rows in set (0.00 sec)
<br/>
為tab_dept增加一個字段descri varchar(20)<br/>
<div class="code" style="position:relative; padding:0px; margin:0px;"><pre class="brush:bash;">mysql> desc tab_dept;
+--------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| deptno | int(11) | YES | | NULL | |
| dname | varchar(20) | YES | | NULL | |
| loc | varchar(40) | YES | | NULL | |
+--------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
mysql> alter table tab_dept add descri varchar(20);
Query OK, 0 rows affected (0.33 sec)
Records: 0 Duplicates: 0 Warnings: 0
mysql> desc tab_dept;
+--------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+--------+-------------+------+-----+---------+-------+
| deptno | int(11) | YES | | NULL | |
| dname | varchar(20) | YES | | NULL | |
| loc | varchar(40) | YES | | NULL | |
| descri | varchar(20) | YES | | NULL | |
+--------+-------------+------+-----+---------+-------+
4 rows in set (0.00 sec)</pre><div class="contentsignin">登入後複製</div></div>在表的第一個位置增加一個字段
<br/>
ALTER TABLE table_name ADD屬性名稱屬性類型first<br/>
mysql> alter table tab_dept add id int first; Query OK, 0 rows affected (0.38 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | varchar(20) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec)
<br/>
ALTER TABLE table_name ADD 屬性名稱屬性類型AFTER 屬性名稱<br/>
mysql> alter table tab_dept add comm varchar(20) after dname; Query OK, 0 rows affected (0.31 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | comm | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | varchar(20) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 6 rows in set (0.00 sec)
<br/>
##ALTER TABLE table_name DROP 屬性名稱<br/>
mysql> alter table tab_dept drop comm; Query OK, 0 rows affected (0.32 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | varchar(20) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec)
欄位修改-修改欄位資料類型<br/>
ALTER TABLE table_name MODIFY 屬性名稱資料類型<br/>#
mysql> alter table tab_dept modify descri int; Query OK, 0 rows affected (0.45 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | int(11) | YES | | NULL | | | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec)
欄位修改-修改欄位名稱
<br/>
ALTER TABLE table_name CHANGE 舊屬性名稱新屬性名稱舊資料類型<br/>
mysql> alter table tab_dept change id deptid int; Query OK, 0 rows affected (0.07 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | deptid | int(11) | YES | | NULL | | | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec)
欄位修改-同時修改欄位名稱與資料類型
<br/>
ALTER TABLE table_name CHANGE 舊屬性名稱新屬性名稱新資料類型<br/>#
mysql> alter table tab_dept change deptid id varchar(32); Query OK, 0 rows affected (0.49 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | varchar(32) | YES | | NULL | | | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec)
修改順序<br/>
ALTER TABLE table_name MODIFY 屬性名稱1 資料類型FIRST|AFTER 屬性名稱2<br/>
<br/>#2個屬性必須存在
將deptno調到第一個位置<br/>#
mysql> alter table tab_dept modify deptno int first; Query OK, 0 rows affected (0.33 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | deptno | int(11) | YES | | NULL | | | id | varchar(32) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec)
mysql> alter table tab_dept modify deptno int after descri; Query OK, 0 rows affected (0.29 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | id | varchar(32) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | int(11) | YES | | NULL | | | deptno | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec) mysql> alter table tab_dept modify deptno int first; Query OK, 0 rows affected (0.34 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> alter table tab_dept modify id int after descri; Query OK, 0 rows affected (0.47 sec) Records: 0 Duplicates: 0 Warnings: 0 mysql> desc tab_dept; +--------+-------------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +--------+-------------+------+-----+---------+-------+ | deptno | int(11) | YES | | NULL | | | dname | varchar(20) | YES | | NULL | | | loc | varchar(40) | YES | | NULL | | | descri | int(11) | YES | | NULL | | | id | int(11) | YES | | NULL | | +--------+-------------+------+-----+---------+-------+ 5 rows in set (0.00 sec)
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