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Case when应用// 如果column_4 = 'IT_PROG' 那么 输出 1.10 * column_3// 如果column_4 = 'ST_CLERK' 那么 输出 1.15 * column_4// 否则 输出 column_3 使用别名 "REVISED_SALARY"SELECT column_1,column_2,column_3 CASE column_4 WHEN 'IT_PROG' THEN 1.10*column_3 WHEN 'ST_CLERK' THEN 1.15*column_3 WHEN 'SA_REP' THEN 1.20*column_3 ELSE column_3 END "REVISED_SALARY"FROM table_name;// SELECT column_1,column_2, SUM(CASE WHEN column_3 = '100' THEN

ORA-00933 错误与 Union all(2010-08-12 15:55:59) 转载ORA-00933 错误与 Union all2009-05-12 14:18union all 连接的两个结果集，只能最后一个结果集中允许出现order by子句，但是该order by子句对整个结果集都产生影响。步骤一：创建测试表a,bSQL> set autot offSQL> create table a as select rownum as id, rownum as name from dual connect by level < 10;Table created.SQL> create table b as select rownum+5 as id, rownum+5 as name from dual connect by level < 10;Table created.SQL> select * from a;