mysql+oracle+sqlserver 查询数据库内所有表的信息，表名，索引，数据行数，备注，长度等等

SELECT

    表名       = case when a.colorder=1 then d.name else '' end,

  索引    = j.name,

  表数据行数 = o.hs,

    表说明     = case when a.colorder=1 then isnull(f.value,'') else '' end,

    字段序号   = a.colorder,

    字段名     = a.name,

    标识       = case when COLUMNPROPERTY( a.id,a.name,'IsIdentity')=1 then '√'else '' end,

    主键       = case when exists(SELECT 1 FROM sysobjects where xtype='PK' and parent_obj=a.id and name in (

                     SELECT name FROM sysindexes WHERE indid in( SELECT indid FROM sysindexkeys WHERE id = a.id AND colid=a.colid))) then '√' else '' end,

    类型       = b.name,

    占用字节数 = a.length,

    长度       = COLUMNPROPERTY(a.id,a.name,'PRECISION'),

    小数位数   = isnull(COLUMNPROPERTY(a.id,a.name,'Scale'),0),

    允许空     = case when a.isnullable=1 then '√'else '' end,

    默认值     = isnull(e.text,''),

    字段说明   = isnull(g.[value],'')

FROM

    syscolumns a

left join

    systypes b

on

    a.xusertype=b.xusertype

inner join

    sysobjects d

on

    a.id=d.id  and d.xtype='U' and  d.name<>'dtproperties'

left join

    syscomments e

on

    a.cdefault=e.id

left join

sys.extended_properties   g

on

    a.id=G.major_id and a.colid=g.minor_id

left join

sys.extended_properties f

on

    d.id=f.major_id and f.minor_id=0

left join

(select  a.name ,b.rows as hs

from sysobjects a inner join sysindexes b

on a.id = b.id

where   a.type = 'u'

and b.indid in (0,1)

) o

on (d.name = o.name)

left join sys.objects as h

on d.name=h.name

left join sys.indexes as j on h.object_id=j.object_id

where h.type<>'s'

order by

    a.id,a.colorder

---------------------------------------------------以上是sqlserver------------------------------------------------------------

SELECT

d.TABLE_NAME tbName ,

COALESCE(t.COMMENTS, ' ') tbDesc,

a.COLUMN_NAME columnName,

a.DATA_TYPE columnType,

a.DATA_LENGTH width,

a.DATA_SCALE precision,

d.NUM_ROWS,

decode(a.NULLABLE,'Y','0','1') notNull,

COALESCE(m.COMMENTS, ' ') comments,

decode(k.uniqueness,'UNIQUE','1','0') uniques,

COALESCE(k.index_name, ' ') indexName,

decode(k.key,'Y','1','0') masterKey

FROM

user_tab_columns a

INNER JOIN user_tables d on a.TABLE_NAME=d.TABLE_NAME

LEFT JOIN user_tab_comments t ON t.TABLE_NAME=d.TABLE_NAME

LEFT JOIN user_col_comments m ON m.COLUMN_NAME=a.COLUMN_NAME AND m.TABLE_NAME=d.TABLE_NAME

LEFT JOIN

(

SELECT e.index_name,u.TABLE_NAME,u.COLUMN_NAME,e.uniqueness,decode(p.constraint_name,NULL,'N','Y') key

from user_indexes e INNER JOIN user_ind_columns u ON e.index_name=u.index_name

LEFT JOIN ( select constraint_name from user_constraints where constraint_type='P' ) p ON e.index_name=p.constraint_name

) k ON k.TABLE_NAME=a.TABLE_NAME and k.COLUMN_NAME=a.COLUMN_NAME

ORDER BY tbName

---------------------------------------------------以上是oracle------------------------------------------------------------

SELECT
        (case ORDINAL_POSITION when 1 then TABLE_NAME ELSE '' end ) '库名',
        ORDINAL_POSITION AS '列的排列顺序',
        COLUMN_COMMENT AS '注释',
    COLUMN_NAME AS '列名',
        IS_NULLABLE AS '是否为空',
        DATA_TYPE AS '数据类型',
        CHARACTER_MAXIMUM_LENGTH AS '字符最大长度',
    COLUMN_DEFAULT AS '默认值',
    NUMERIC_PRECISION AS '数值精度(最大位数)',
    NUMERIC_SCALE AS '小数精度',
    COLUMN_TYPE AS 列类型,
    COLUMN_KEY 'KEY',
    EXTRA AS '额外说明'
   
FROM
    information_schema.`COLUMNS`
WHERE
    TABLE_SCHEMA = 'ceshi' （ceshi替换为库名即可）
ORDER BY
    TABLE_NAME,
    ORDINAL_POSITION;

---------------------------------------------------以上是mysql------------------------------------------------------------