Oracle 和 Mysql 查询表字段信息

查看格式：
oracle:

SELECT
	tc.column_name AS "columnName",
	cc.comments AS "comments",
	tc.data_type AS "dataType",
	tc.data_length AS "dataLength",
	tc.nullable AS "nullable",
	(
		SELECT
			COUNT (*)
		FROM
			user_cons_columns U,
			user_constraints c
		WHERE
			U .constraint_name = c.constraint_name
		AND c.constraint_type = \'P\'
		AND U .table_name = tc.table_name
		AND U .column_name = tc.column_name
	) AS "primaryKey"
FROM
	user_tab_columns tc,
	user_col_comments cc
WHERE
	tc.table_name = cc.table_name
AND tc.column_name = cc.column_name
AND tc.table_name = \'SYS_TASK\';

mysql:

SELECT
	COLUMN_NAME AS "columnName",
	COLUMN_COMMENT AS "comments",
	DATA_TYPE AS "dataType",
	CHARACTER_MAXIMUM_LENGTH AS "dataLength",
	(case when IS_NULLABLE=\'NO\' then \'N\' else \'Y\' end) AS "nullable",
	(case when COLUMN_KEY=\'PRI\' then \'1\' else \'0\' end) AS "primaryKey"
FROM
	information_schema.`COLUMNS`
WHERE
	TABLE_SCHEMA = \'mgl\'
AND TABLE_NAME = \'SYS_TASK\';