mysql、postgresql查詢表字所有字段

1、mysql查詢表字所有字段

• 第一種：

SHOW FULL COLUMNS FROM table_name;

解釋：

Field ：字段名
Type：字段類型
Collation：字符集（mysql 5.0以上有）
Null ：是否可以為NULL
Key：索引（PRI,unique,index)
Default：缺省值
Extra：額外（是否 auto_increment)
Privileges：權限
Comment：備注（mysql 5.0以上有)

• 第二種：

SELECT
	COLUMN_NAME 列名,
	COLUMN_COMMENT 名稱,
	COLUMN_TYPE 數據類型,
	DATA_TYPE 字段類型,
	CHARACTER_MAXIMUM_LENGTH 長度,
	IS_NULLABLE 是否必填,
	COLUMN_DEFAULT 描述 
FROM
	INFORMATION_SCHEMA.COLUMNS 
WHERE
	table_schema = 'dbname' 
	AND table_name = 'table'

2、postgresql查看表字段

SELECT a.attnum,
a.attname AS field,
t.typname AS type,
a.attlen AS length,
a.atttypmod AS lengthvar,
a.attnotnull AS notnull,
b.description AS comment
FROM pg_class c,
pg_attribute a
LEFT OUTER JOIN pg_description b ON a.attrelid=b.objoid AND a.attnum = b.objsubid,
pg_type t
WHERE c.relname = 't_uc_login'
and a.attnum > 0
and a.attrelid = c.oid
and a.atttypid = t.oid
ORDER BY a.attnum;