精典sql总结
--删除表中的重复记录
DELETE FROM table_name a
????? WHERE ROWID >
?????????????? (SELECT MIN (ROWID)
????????????????? FROM table_name b
???????????????? WHERE b.pk_column_1 = a.pk_column_1
?????????????????? AND b.pk_column_2 = a.pk_column_2);
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2. 查找表空间datafile
SQL>select * from dba_data_files where tablespace_name = ‘UNDOTBS1′;
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3.查看表空占用情况
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?SELECT UPPER(F.TABLESPACE_NAME) "表空间名",D.TOT_GROOTTE_MB "表空间大小(M)",?????? D.TOT_GROOTTE_MB - F.TOTAL_BYTES "已使用空间(M)",
?????? TO_CHAR(ROUND((D.TOT_GROOTTE_MB - F.TOTAL_BYTES) /?? D.TOT_GROOTTE_MB * 100, 2),'990.99') "使用比",??? F.TOTAL_BYTES "空闲空间(M)",?????? F.MAX_BYTES "最大块(M)"
FROM (SELECT TABLESPACE_NAME, ROUND(SUM(BYTES) / (1024 * 1024),? 2) TOTAL_BYTES, ROUND(MAX(BYTES) /???????????? (1024 * 1024),?? 2) MAX_BYTES ???? FROM SYS.DBA_FREE_SPACE GROUP BY TABLESPACE_NAME) F,
?? (SELECT DD.TABLESPACE_NAME,ROUND(SUM(DD.BYTES) / (1024 * 1024), 2) TOT_GROOTTE_MB FROM SYS.DBA_DATA_FILES DD GROUP BY DD.TABLESPACE_NAME) D WHERE D.TABLESPACE_NAME = F.TABLESPACE_NAME ORDER BY 4 DESC
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http://blog.chinabyte.com/a/578694.html?
