FIRST and LAST are very similar functions. Both are aggregate and analytic functions that operate on a set of values from a set of rows that rank as[……]

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WITH xo AS
(SELECT ‘201401’ AS Y, ‘aa’ AS V
FROM DUAL
UNION ALL
SELECT ‘201401’ AS Y, ‘bb’ AS V
FROM DUAL
UNION ALL
SELECT ‘201401’ AS Y, ‘aa’ AS V
FR[……]

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create or replace procedure sp_GenerateSp(t_name IN VARCHAR2) as
v_count            NUMBER;         –count
v_name             VARCHAR2(50);
v_col    [……]

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SQL*Plus Security
限制哪些用户在SQL*Plus里能够执行哪些命令以及不能执行哪些命令

oracle是用system用户下的PRODUCT_USER_PROFILE (PUP)表来进行的限制。提供了产品级别的安全,用户级安全（SQL GRANT和REVOKE命令和用户角色）相互补[……]

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1. gv$instance

SQL> desc gv$instance;
Name Null? Type
—————————————– ——– —————————-
INST_ID NUMB[……]

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create or replace procedure show_space
( p_segname in varchar2,
p_owner in varchar2 default user,
p_type in varchar2 default ‘[……]

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Oracle比较一列的最大值或者最小值，我们会不假思索地用MAX和MIN函数，但是对于比较一行的最大值或最小值呢？是不是日常用的少，很多人都不知道有ORACLE也有内置函数实现这个功能：COALESCE / GREATEST / LEAST.

1. COALESCE 返回该表达式列[……]

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