一、普通查询
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/*查询表数据*/select * from STU |
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/*取出前3行数据*/select * from stu where ROWNUM<=3 |
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/*模糊查询*/select * from stu where stu_id like 'stu001%' |
说明：通配符“%”代表一个或者多个字符，通配符“_”代表一个字符。
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/*别名*/select STU_ID as 学号 from stu |
二、联合查询
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/*普通联合查询*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU, KC WHERE STU.KC_NO = KC.KC_NO |
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/*联合查询*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU INNER JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID |
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/*左连接*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU LEFT JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID |
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/*右连接*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU RIGHT JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID |
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/*全连接*/SELECT STU.STU_NAME, STU.STU_AGE, KC.KC_NAME FROM STU FULL JOIN KC ON STU.KC_NO = KC.KC_NO ORDER BY STU.STU_ID |
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/*UNION关键字，联合两个表某些字段*/SELECT STU_NAME FROM STU UNION SELECT KC_NAME FROM KC |
