1. OR与<>连接容易出错
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DROP TABLE t;
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CREATE TABLE t(col1 INT, col2 INT);
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INSERT INTO t VALUES(22, 19);
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INSERT INTO t VALUES(21, 22);
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INSERT INTO t VALUES(90, 40);
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COMMIT;
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SELECT * FROM t;
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COL1 COL2
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---------- ----------
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22 19
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21 22
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90 40
2. OR与AND组合要注意括号
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--从数据字典dba_segements中查询表空间名为TEMP,并且owner字段以TEST_或ZHJS打头的记录
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--错误写法
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SELECT * FROM dba_segments
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WHERE tablespace_name = \'TEMP\' AND owner LIKE \'TEST_%\' OR owner LIKE \'ZHJS_%\';
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--正确的写法
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SELECT * FROM dba_segments
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WHERE tablespace_name = \'TEMP\' AND (owner LIKE \'TEST_%\' OR owner LIKE \'ZHJS_%\');
来自 “ ITPUB博客 ” ,链接:https://blog.itpub.net/17013648/viewspace-1071089/
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