Sql查询数据库中表的使用空间以及表结构

一 . Sql server 查询数据库中表的使用空间及表结构

1.查询单表

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EXEC sp_spaceused 'dbo.tablename'

2.查询所有表

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SELECT t.NAME AS TableName,  -- 表明s.Name AS SchemaName,  -- 架构名
p.rows AS RowCounts,  --  总行数
SUM(a.total_pages) * 8 AS TotalSpaceKB, --总空间kb
CAST(ROUND(((SUM(a.total_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS TotalSpaceMB,
SUM(a.used_pages) * 8 AS UsedSpaceKB,
CAST(ROUND(((SUM(a.used_pages) * 8) / 1024.00), 2) AS NUMERIC(36, 2)) AS UsedSpaceMB, --使用空间
(SUM(a.total_pages) - SUM(a.used_pages)) * 8 AS UnusedSpaceKB, -- 未使用空间
CAST(ROUND(((SUM(a.total_pages) - SUM(a.used_pages)) * 8) / 1024.00, 2) AS NUMERIC(36, 2)) AS UnusedSpaceMB
FROM
sys.tables t
INNER JOIN
sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN
sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN
sys.allocation_units a ON p.partition_id = a.container_id
LEFT OUTER JOIN
sys.schemas s ON t.schema_id = s.schema_id
WHERE
t.NAME NOT LIKE 'dt%'    --  表名
AND t.is_ms_shipped = 0
AND i.OBJECT_ID > 255   AND  p.rows>80000    -- 表的总条数大于80000
GROUP BY
t.Name, s.Name, p.Rows
ORDER BY
t.Name

3.查询表结构

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SELECT  CASE WHEN col.colorder = 1 THEN obj.name
                  ELSE ''
             END AS 表名,
        col.colorder AS 序号 ,
        col.name AS 列名 ,
        ISNULL(ep.[value], '') AS 列说明 ,
        t.name AS 数据类型 ,
        col.length AS 长度 ,
        ISNULL(COLUMNPROPERTY(col.id, col.name, 'Scale'), 0) AS 小数位数 ,
        CASE WHEN COLUMNPROPERTY(col.id, col.name, 'IsIdentity') = 1 THEN '√'
             ELSE ''
        END AS 标识 ,
        CASE WHEN EXISTS ( SELECT   1
                           FROM     dbo.sysindexes si
                                    INNER JOIN dbo.sysindexkeys sik ON si.id = sik.id
                                                              AND si.indid = sik.indid
                                    INNER JOIN dbo.syscolumns sc ON sc.id = sik.id
                                                              AND sc.colid = sik.colid
                                    INNER JOIN dbo.sysobjects so ON so.name = si.name
                                                              AND so.xtype = 'PK'
                           WHERE    sc.id = col.id
                                    AND sc.colid = col.colid ) THEN '√'
             ELSE ''
        END AS 主键 ,
        CASE WHEN col.isnullable = 1 THEN '√'
             ELSE ''
        END AS 允许空 ,
        ISNULL(comm.text, '') AS 默认值
FROM    dbo.syscolumns col
        LEFT  JOIN dbo.systypes t ON col.xtype = t.xusertype
        inner JOIN dbo.sysobjects obj ON col.id = obj.id
                                         AND obj.xtype = 'U'
                                         AND obj.status >= 0
        LEFT  JOIN dbo.syscomments comm ON col.cdefault = comm.id
        LEFT  JOIN sys.extended_properties ep ON col.id = ep.major_id
                                                      AND col.colid = ep.minor_id
                                                      AND ep.name = 'MS_Description'
        LEFT  JOIN sys.extended_properties epTwo ON obj.id = epTwo.major_id
                                                         AND epTwo.minor_id = 0
                                                         AND epTwo.name = 'MS_Description'
WHERE   obj.name = 'T_Contract'--数据库表名  

ORDER BY col.colorder ;

二.MySql查询数据库中表的使用空间及表结构

1.查询表结构

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SELECT
    COLUMN_NAME 列名,
    COLUMN_TYPE 数据类型,
    DATA_TYPE 字段类型,
    CHARACTER_MAXIMUM_LENGTH 长度,
     case WHEN  IS_NULLABLE='YES' THEN '√'  ELSE ''  END 是否为空,
    COLUMN_DEFAULT 默认值,
    COLUMN_COMMENT 列说明
FROM
    INFORMATION_SCHEMA.COLUMNS
WHERE table_schema='aaa'           -- 数据库名
      and table_name  = 'bbb'      -- 表名

2.查询表所有表

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 select * from information_schema.tables where table_schema='jepaas'  --数据库名