1、MySQL

表查询：

SELECT   '' AS TABLE_SCHEMA,  TABLE_NAME,  TABLE_COMMENT FROMinformation_schema.TABLES WHERE TABLE_SCHEMA = '${db}'  

字段查询：

SELECT   '' AS TABLE_SCHEMA,  c.TABLE_NAME,  c.COLUMN_NAME,  c.COLUMN_TYPE,  '' AS COLUMN_LENGTH,  IF(c.COLUMN_KEY = 'PRI', 1, 0) COLUMN_KEY,  IF(c.IS_NULLABLE = 'NO', 1, 0) AS NULLABLE,  c.COLUMN_COMMENT FROM  information_schema.COLUMNS c WHERE c.TABLE_SCHEMA = '${db}' 

2、Oracle

表查询：

SELECT   OWNER AS TABLE_SCHEMA,  TABLE_NAME AS TABLE_NAME,  COMMENTS AS TABLE_COMMENT from  all_tab_comments WHERE OWNER NOT IN (    'ANONYMOUS',    'APEX_030200',    'APEX_PUBLIC_USER',    'APPQOSSYS',    'AURORA$JIS$UTILITY$',    'AURORA$ORB$UNAUTHENTICATED',    'BI',    'CTXSYS',    'DBSNMP',    'DIP',    'DMSYS',    'DVF',    'DVSYS',    'EXFSYS',    'FLOWS_040100',    'FLOWS_FILES',    'HR',    'IX',    'LBACSYS',    'MDDATA',    'MDSYS',    'MGMT_VIEW',    'OAS_PUBLIC',    'ODM',    'ODM_MTR',    'OE',    'OLAPSYS',    'ORACLE_OCM',    'ORDDATA',    'ORDPLUGINS',    'ORDSYS',    'OSE$HTTP$ADMIN',    'OUTLN',    'OWBSYS',    'OWBSYS_AUDIT',    'PERFSTAT',    'PM',    'QS',    'QS_ADM',    'QS_CB',    'QS_CBADM',    'QS_CS',    'QS_ES',    'QS_OS',    'QS_WS',    'REPADMIN',    'RMAN',    'SCOTT',    'SH',    'SI_INFORMTN_SCHEMA',    'SPATIAL_CSW_ADMIN_USR',    'SPATIAL_WFS_ADMIN_USR',    'SYS',    'SYSMAN',    'SYSTEM',    'TRACESVR',    'TSMSYS',    'WEBSYS',    'WKPROXY',    'WKSYS',    'WKUSER',    'WK_TEST',    'WMSYS',    'XDB',    'XS$NULL'  )

字段查询：

SELECT   tc.OWNER AS TABLE_SCHEMA,  tc.TABLE_NAME AS TABLE_NAME,  tc.COLUMN_NAME,  tc.DATA_TYPE AS COLUMN_TYPE,  tc.DATA_LENGTH AS COLUMN_LENGTH,  NVL2 (ic.COLUMN_POSITION, 'YES', '') AS COLUMN_KEY,  tc.NULLABLE,  cc.COMMENTS AS COLUMN_COMMENT FROM  all_tab_columns tc   LEFT JOIN all_col_comments cc     ON cc.OWNER = tc.OWNER     AND cc.TABLE_NAME = tc.TABLE_NAME     AND cc.COLUMN_NAME = tc.COLUMN_NAME   LEFT JOIN ALL_IND_COLUMNS ic     ON ic.TABLE_OWNER = tc.OWNER     AND ic.TABLE_NAME = tc.TABLE_NAME     AND ic.COLUMN_NAME = tc.COLUMN_NAME 

3、SqlServer

表查询：

SELECT   '' AS TABLE_SCHEMA,  a.name AS TABLE_NAME,  CONVERT(    NVARCHAR (255),    ISNULL(g.[ VALUE ], '-')  ) AS TABLE_COMMENT FROM  sys.tables a   LEFT JOIN sys.extended_properties g     ON (      a.object_id = g.major_id       AND g.minor_id = 0    )

字段查询：

SELECT   '' AS TABLE_SCHEMA,  d.name AS TABLE_NAME,  a.name AS COLUMN_NAME,  b.name AS COLUMN_TYPE,  COLUMNPROPERTY (a.id, a.name, 'PRECISION') AS COLUMN_LENGTH,  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 '1'     ELSE '0'   END AS COLUMN_KEY,  CASE    WHEN a.isnullable = 1     THEN '1'     ELSE '0'   END AS NULLABLE,  CONVERT(NVARCHAR (255), ISNULL(g.[ VALUE ], '')) AS COLUMN_COMMENT 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'   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 

4、SqlServer_low（低版本）

表查询：

SELECT   '' AS TABLE_SCHEMA,  a.name AS TABLE_NAME,  CONVERT(NVARCHAR (255), ISNULL(b.[ VALUE ], '')) AS TABLE_COMMENT FROM  ..sysobjects a   LEFT JOIN sysproperties b     ON a.id = b.id     AND b.smallid = 0 WHERE a.xtype = 'U' 

字段查询：

SELECT   '' AS TABLE_SCHEMA,  d.name AS TABLE_NAME,  a.name AS COLUMN_NAME,  b.name AS COLUMN_TYPE,  COLUMNPROPERTY (a.id, a.name, 'PRECISION') AS COLUMN_LENGTH,  CASE    WHEN EXISTS     (SELECT       1     FROM      sysobjects     WHERE xtype = 'PK'       AND NAME IN       (SELECT         NAME       FROM        sysindexes       WHERE indid IN         (SELECT           indid         FROM          sysindexkeys         WHERE id = a.id           AND colid = a.colid)))     THEN '1'     ELSE '0'   END AS COLUMN_KEY,  CASE    WHEN a.isnullable = 1     THEN '1'     ELSE '0'   END AS NULLABLE,  CONVERT(NVARCHAR (255), ISNULL(g.[ VALUE ], '')) AS COLUMN_COMMENT FROM  syscolumns a   LEFT OUTER JOIN systypes b     ON a.xtype = b.xusertype   INNER JOIN sysobjects d     ON a.id = d.id     AND d.xtype = 'U'   LEFT OUTER JOIN syscomments e     ON a.cdefault = e.id   LEFT OUTER JOIN sysproperties g     ON a.id = g.id     AND a.colid = g.smallid 

5、PostgreSQL

表查询：

WITH tmp_tab AS (SELECT   pc.oid AS ooid,  pn.nspname,  pc.* FROM  pg_class pc   LEFT OUTER JOIN pg_namespace pn     ON pc.relnamespace = pn.oid WHERE pc.relkind IN ('r')   AND pn.nspname NOT IN (    'pg_catalog',    'information_schema'  )   AND pn.nspname NOT LIKE 'pg_toast%'   AND pc.oid NOT IN   (SELECT     inhrelid   FROM    pg_inherits)   AND pc.relname NOT LIKE '%peiyb%' ORDER BY pc.relname),tmp_desc AS (SELECT   pd.* FROM  pg_description pd WHERE pd.objsubid = 0) SELECT   tab.nspname AS TABLE_SCHEMA,  tab.relname AS TABLE_NAME,  de.description AS TABLE_COMMENT FROM  tmp_tab tab   LEFT OUTER JOIN tmp_desc de     ON tab.ooid = de.objoid 

字段查询：

WITH tmp_tab AS (SELECT   pc.oid AS ooid,  pn.nspname,  pc.* FROM  pg_class pc   LEFT OUTER JOIN pg_namespace pn     ON pc.relnamespace = pn.oid WHERE pc.relkind IN ('r')   AND pn.nspname NOT IN (    'pg_catalog',    'information_schema'  )   AND pn.nspname NOT LIKE 'pg_toast%'   AND pc.oid NOT IN   (SELECT     inhrelid   FROM    pg_inherits)   AND pc.relname NOT LIKE '%peiyb%'),tmp_col AS (SELECT   pa.*,  pt.typname FROM  pg_attribute pa   LEFT JOIN pg_type pt     ON pa.atttypid = pt.oid WHERE pa.attnum > 0),tmp_desc AS (SELECT   pd.* FROM  pg_description pd WHERE pd.objsubid <> 0) SELECT   tab.nspname AS TABLE_SCHEMA,  tab.relname AS TABLE_NAME,  tc.attname AS COLUMN_NAME,  CASE    WHEN tc.attlen < 0     THEN tc.atttypmod - 4     ELSE tc.attlen   END COLUMN_LENGTH,  tc.typname AS COLUMN_TYPE,  '' AS COLUMN_KEY,  CASE    WHEN tc.attnotnull = 't'     THEN '1'     ELSE '0'   END NULLABLE,  de.description AS COLUMN_COMMENT FROM  tmp_tab tab   LEFT OUTER JOIN tmp_col tc     ON tab.ooid = tc.attrelid   LEFT OUTER JOIN tmp_desc de     ON tc.attrelid = de.objoid     AND tc.attnum = de.objsubid WHERE tc.attisdropped = FALSE 

6、Vertica

表查询：

SELECT   schema_name AS TABLE_SCHEMA,  table_name AS TABLE_NAME,  remarks AS TABLE_COMMENT FROM  all_tables WHERE table_type = 'TABLE' 

字段查询：

SELECT   a.table_schema AS TABLE_SCHEMA,  a.table_name AS TABLE_NAME,  a.column_name AS COLUMN_NAME,  a.data_type AS COLUMN_TYPE,  '' AS COLUMN_LENGTH,  CASE    WHEN a.is_identity = 'true'     THEN '1'     ELSE '0'   END AS COLUMN_KEY,  CASE    WHEN a.is_nullable = 'true'     THEN '1'     ELSE '0'   END AS NULLABLE,  b.comment AS COLUMN_COMMENT FROM  COLUMNS a   LEFT JOIN comments b     ON a.table_name || '_super.' || a.column_name = b.object_name WHERE a.is_system_table = 'false'   AND b.object_type = 'COLUMN' 

7、DM7

表查询：

SELECT   a.OWNER AS TABLE_SCHEMA,  a.TABLE_NAME,  NVL (b.COMMENT $, '') AS TABLE_COMMENT FROM  ALL_TABLES a   LEFT JOIN SYSTABLECOMMENTS b     ON a.OWNER = b.SCHNAME     AND a.TABLE_NAME = b.TVNAME WHERE a.STATUS = 'VALID' 

字段查询：

SELECT   a.OWNER AS TABLE_SCHEMA,  a.TABLE_NAME,  a.COLUMN_NAME,  a.DATA_TYPE AS COLUMN_TYPE,  a.DATA_LENGTH AS COLUMN_LENGTH,  DECODE(d.CONSTRAINT_TYPE, 'P', 'YES', '') AS COLUMN_KEY,  a.NULLABLE,  NVL (b.COMMENT $, '') AS COLUMN_COMMENT FROM  ALL_TAB_COLUMNS a   LEFT JOIN SYSCOLUMNCOMMENTS b     ON a.OWNER = b.SCHNAME     AND a.TABLE_NAME = b.TVNAME     AND a.COLUMN_NAME = b.COLNAME   LEFT JOIN ALL_CONS_COLUMNS c     ON b.SCHNAME = c.OWNER     AND b.TVNAME = c.TABLE_NAME     AND b.COLNAME = c.COLUMN_NAME   LEFT JOIN ALL_CONSTRAINTS d     ON c.CONSTRAINT_NAME = d.CONSTRAINT_NAME     AND c.OWNER = d.OWNER     AND c.TABLE_NAME = d.TABLE_NAME 

8、GBase

表查询：

SELECT   '' AS TABLE_SCHEMA,  TABLE_NAME,  TABLE_COMMENT FROM  information_schema.TABLES WHERE TABLE_SCHEMA = '${db}' 

字段查询：

SELECT   '' AS TABLE_SCHEMA,  c.TABLE_NAME,  c.COLUMN_NAME,  c.COLUMN_TYPE,  '' AS COLUMN_LENGTH,  IF(c.COLUMN_KEY = 'PRI', 1, 0) COLUMN_KEY,  IF(c.IS_NULLABLE = 'NO', 1, 0) AS NULLABLE,  c.COLUMN_COMMENT FROM  information_schema.COLUMNS c WHERE c.TABLE_SCHEMA = '${db}'