plsql如何导表结构

在PL/SQL中，可以使用以下SQL语句来导出表结构：

select T1.TABLE_NAME as "表名称", T3.COMMENTS as "表说明", T1.COLUMN_NAME AS "字段名称", T1.DATA_TYPE AS "数据类型", T1.DATA_LENGTH AS "长度", T1.NULLABLE AS "是否为空", T2.COMMENTS AS "字段说明", T1.DATA_DEFAULT "默认值" 
from COLS T1 
LEFT JOIN USER_COL_COMMENTS T2 ON T1.TABLE_NAME = T2.TABLE_NAME AND T1.COLUMN_NAME = T2.COLUMN_NAME 
LEFT JOIN USER_TAB_COMMENTS T3 ON T1.TABLE_NAME = T3.TABLE_NAME 
WHERE NOT EXISTS ( 
    select T4.OBJECT_NAME 
    FROM USER_OBJECTS T4 
    where T4.OBJECT_TYPE = 'TABLE' AND T4.TEMPORARY = 'Y' AND T4.OBJECT_NAME = T1.TABLE_NAME 
) 
AND T1.TABLE_NAME = upper('emp') -- 需要导出schema的表名 
order by T1.TABLE_NAME, T1.COLUMN_ID;

这个SQL语句会查询出指定表的结构信息，包括表名、字段名、数据类型、长度、是否为空、默认值等。同时，还会获取表和字段的注释信息。[1]

请注意，你需要将其中的`upper('emp')`替换为你要导出表结构的具体表名。