摘要：多表插入语句分为以下四种：①无条件INSERT。②有条件INSERT ALL。③转置INSERT。④有条件INSERT FIRST。首先创建测试用表：CREATE TABLE emp( empno NUMBER(4), ename VARCHAR2(10), job VARCHAR... 阅读全文

摘要：有时排序的要求会比较复杂，比如：领导对工资在1000到2000元之间的员工更感兴趣，于是要求工资在这个范围的员工要排在前面，以便优先查看。创建测试用表：CREATE OR REPLACE VIEW v ASSELECT 'MARTIN' AS ename, 950 AS sal FROM DUALU... 阅读全文

摘要：oracle排序的时候默认空值是最大的，如果想要自己规定空值显示的位置，可以使用关键字NULLS FIRST和NULLS LAST。创建测试用表：CREATE OR REPLACE VIEW v ASSELECT 1 AS c FROM DUALUNION ALLSELECT NULL AS c F... 阅读全文

摘要：语法格式： TRANSLATE(expr, from_string, to_string)示例如下：SELECT TRANSLATE('ab 你好 bcdefg', 'abcdefg', '1234567') FROM DUAL;from_string与to_string以字符为单位，对应字符一一替... 阅读全文

摘要：如果要对计算列排序，可以为计算列指定别名，然后按别名排序。创建测试用表：CREATE OR REPLACE VIEW v ASSELECT 3 AS a, 4 AS b FROM DUALUNION ALLSELECT 2 AS a, 3 AS b FROM DUALUNION ALLSELECT ... 阅读全文

摘要：创建测试用表：CREATE OR REPLACE VIEW V ASSELECT 'a' AS c FROM dualUNION ALLSELECT 'b' AS c FROM dualUNION ALLSELECT 'c' AS c FROM dualUNION ALLSELECT 'd' AS ... 阅读全文

摘要：创建测试用表：CREATE OR REPLACE VIEW V ASSELECT 'a' AS c FROM dualUNION ALLSELECT 'b' AS c FROM dualUNION ALLSELECT 'c' AS c FROM dualUNION ALLSELECT 'd' AS ... 阅读全文

摘要：创建测试用表：CREATE OR REPLACE VIEW v ASSELECT NULL AS c1, NULL AS c2, '1' AS c3, NULL AS c4, '2' AS c5 FROM dualUNION ALLSELECT NULL AS c1, NULL AS c2, NUL... 阅读全文