oracle查询,Oracle数据库查询技巧与优化策略

当然，Oracle是一个关系型数据库管理系统，它使用SQL（结构化查询语言）来查询和管理数据。下面是一些基本的Oracle查询示例：

1. 查询所有数据： ```sql SELECT FROM table_name; ```

2. 查询特定列： ```sql SELECT column1, column2 FROM table_name; ```

3. 条件查询： ```sql SELECT FROM table_name WHERE condition; ```

4. 排序查询： ```sql SELECT FROM table_name ORDER BY column_name; ```

5. 分组查询： ```sql SELECT column_name, COUNT FROM table_name GROUP BY column_name; ```

6. 连接查询： ```sql SELECT FROM table1 JOIN table2 ON table1.column_name = table2.column_name; ```

7. 子查询： ```sql SELECT FROM table_name WHERE column_name IN ; ```

8. 更新数据： ```sql UPDATE table_name SET column_name = value WHERE condition; ```

9. 删除数据： ```sql DELETE FROM table_name WHERE condition; ```

10. 插入数据： ```sql INSERT INTO table_name VALUES ; ```

11. 创建表： ```sql CREATE TABLE table_name ; ```

12. 创建索引： ```sql CREATE INDEX index_name ON table_name ; ```

13. 创建视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

14. 创建序列： ```sql CREATE SEQUENCE sequence_name START WITH 1 INCREMENT BY 1; ```

15. 创建同义词： ```sql CREATE SYNONYM synonym_name FOR table_name; ```

16. 创建用户： ```sql CREATE USER username IDENTIFIED BY password; ```

17. 授予权限： ```sql GRANT privilege ON object_name TO username; ```

18. 回收权限： ```sql REVOKE privilege ON object_name FROM username; ```

19. 创建角色： ```sql CREATE ROLE role_name; ```

20. 角色授权： ```sql GRANT role_name TO username; ```

21. 角色回收： ```sql REVOKE role_name FROM username; ```

22. 创建触发器： ```sql CREATE TRIGGER trigger_name BEFORE/AFTER INSERT/UPDATE/DELETE ON table_name FOR EACH ROW BEGIN trigger body END; ```

23. 创建存储过程： ```sql CREATE PROCEDURE procedure_name AS BEGIN procedure body END; ```

24. 创建函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

25. 创建包： ```sql CREATE PACKAGE package_name AS package specification END; ```

26. 创建包体： ```sql CREATE PACKAGE BODY package_name AS package body END; ```

27. 创建数据库 ```sql CREATE DATABASE LINK link_name CONNECT TO username IDENTIFIED BY password USING 'database_name'; ```

28. 创建物化视图： ```sql CREATE MATERIALIZED VIEW view_name REFRESH COMPLETE ON DEMAND AS SELECT FROM table_name; ```

29. 创建物化视图日志： ```sql CREATE MATERIALIZED VIEW LOG ON table_name WITH ROWID; ```

30. 创建作业： ```sql BEGIN DBMS_SCHEDULER.CREATE_JOB ; END; ```

31. 创建目录： ```sql CREATE DIRECTORY directory_name AS '/path/to/directory'; ```

32. 创建外部表： ```sql CREATE TABLE external_table_name ORGANIZATION EXTERNAL LOCATION qwe2; ```

33. 创建维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

34. 创建等级关系： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

35. 创建等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

36. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

37. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

38. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

39. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

41. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

42. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

43. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

44. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

45. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

46. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

47. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

49. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

50. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

51. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

52. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

53. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

54. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

55. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

57. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

58. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

59. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

60. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

61. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

62. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

63. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

65. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

66. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

67. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

68. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

69. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

70. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

71. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

73. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

74. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

75. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

76. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

77. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

78. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

79. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

81. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

82. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

83. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

84. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

85. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

86. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

87. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

89. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

90. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

91. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

92. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

93. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

94. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

95. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

97. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

98. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

99. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

100. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

101. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

102. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

103. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

105. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

106. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

107. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

108. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

109. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

110. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

111. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name GROUP BY column_name; ```

6. 连接查询： ```sql SELECT FROM table1 JOIN table2 ON table1.column_name = table2.column_name; ```

7. 子查询： ```sql SELECT FROM table_name WHERE column_name IN ; ```

8. 更新数据： ```sql UPDATE table_name SET column_name = value WHERE condition; ```

9. 删除数据： ```sql DELETE FROM table_name WHERE condition; ```

10. 插入数据： ```sql INSERT INTO table_name VALUES ; ```

11. 创建表： ```sql CREATE TABLE table_name ; ```

12. 创建索引： ```sql CREATE INDEX index_name ON table_name ; ```

13. 创建视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

14. 创建序列： ```sql CREATE SEQUENCE sequence_name START WITH 1 INCREMENT BY 1; ```

15. 创建同义词： ```sql CREATE SYNONYM synonym_name FOR table_name; ```

16. 创建用户： ```sql CREATE USER username IDENTIFIED BY password; ```

17. 授予权限： ```sql GRANT privilege ON object_name TO username; ```

18. 回收权限： ```sql REVOKE privilege ON object_name FROM username; ```

19. 创建角色： ```sql CREATE ROLE role_name; ```

20. 角色授权： ```sql GRANT role_name TO username; ```

21. 角色回收： ```sql REVOKE role_name FROM username; ```

22. 创建触发器： ```sql CREATE TRIGGER trigger_name BEFORE/AFTER INSERT/UPDATE/DELETE ON table_name FOR EACH ROW BEGIN trigger body END; ```

23. 创建存储过程： ```sql CREATE PROCEDURE procedure_name AS BEGIN procedure body END; ```

24. 创建函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

25. 创建包： ```sql CREATE PACKAGE package_name AS package specification END; ```

26. 创建包体： ```sql CREATE PACKAGE BODY package_name AS package body END; ```

27. 创建数据库 ```sql CREATE DATABASE LINK link_name CONNECT TO username IDENTIFIED BY password USING 'database_name'; ```

28. 创建物化视图： ```sql CREATE MATERIALIZED VIEW view_name REFRESH COMPLETE ON DEMAND AS SELECT FROM table_name; ```

29. 创建物化视图日志： ```sql CREATE MATERIALIZED VIEW LOG ON table_name WITH ROWID; ```

30. 创建作业： ```sql BEGIN DBMS_SCHEDULER.CREATE_JOB ; END; ```

31. 创建目录： ```sql CREATE DIRECTORY directory_name AS '/path/to/directory'; ```

32. 创建外部表： ```sql CREATE TABLE external_table_name ORGANIZATION EXTERNAL LOCATION qwe2; ```

33. 创建维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

34. 创建等级关系： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

35. 创建等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

36. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

37. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

38. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

39. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

41. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

42. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

43. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

44. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

45. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

46. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

47. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

49. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

50. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

51. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

52. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

53. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

54. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

55. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

57. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

58. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

59. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name ; ```

60. 创建分析函数： ```sql CREATE FUNCTION function_name RETURN datatype AS BEGIN function body RETURN value; END; ```

61. 创建分析视图： ```sql CREATE VIEW view_name AS SELECT FROM table_name; ```

62. 创建分析窗口函数： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

63. 创建分析查询： ```sql SELECT column_name, ANALYTIC_FUNCTION OVER FROM table_name; ```

65. 创建分析维度： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name; ```

66. 创建分析等级： ```sql CREATE DIMENSION dimension_name LEVEL level_name IS column_name RELATIVE LEVELS ; ```

67. 创建分析等级层次： ```sql CREATE DIMENSION dimension_name HIERARCHY hierarchy_name qwe1 level_name1,

Oracle数据库查询技巧与优化策略

Oracle数据库作为全球最流行的关系型数据库之一，其强大的查询功能是数据库管理者和开发者日常工作中不可或缺的部分。本文将介绍一些Oracle数据库查询的技巧和优化策略，帮助您更高效地处理数据。

一、Oracle查询基础

在开始深入探讨查询优化之前，我们先回顾一下Oracle数据库查询的基础知识。

1.1 数据类型

Oracle数据库支持多种数据类型，包括数字、字符、日期/时间、布尔值等。了解并正确使用这些数据类型对于编写高效的查询至关重要。

1.2 关系运算符

关系运算符如等于（=）、不等于（）、大于（>）、小于（1.3 逻辑运算符

逻辑运算符如AND、OR、NOT等用于组合多个条件。

二、Oracle查询技巧

2.1 使用索引

索引是提高查询性能的关键。通过在经常用于查询条件的列上创建索引，可以显著减少查询所需的时间。

2.2 使用LIKE查询

LIKE查询用于匹配包含特定模式的字符串。使用通配符（%和_）可以更灵活地进行搜索。

2.3 使用BETWEEN查询

BETWEEN查询用于查找指定范围内的数据。它可以简化查询语句，提高可读性。

2.4 使用聚合函数

聚合函数如SUM、AVG、COUNT等用于对一组数据进行计算。它们在处理大量数据时非常有用。

三、Oracle查询优化策略

3.1 分析执行计划

执行计划是Oracle数据库在执行查询时生成的内部工作流程。通过分析执行计划，您可以了解查询的执行方式，并找出潜在的瓶颈。

3.2 避免全表扫描

全表扫描是查询性能的杀手。通过使用索引和适当的查询条件，可以避免全表扫描，从而提高查询速度。

3.3 优化查询语句

避免使用SELECT ；

使用别名简化查询语句；

避免在WHERE子句中使用函数；

使用JOIN代替子查询。

3.4 使用分区表

分区表可以将大型表分解为更小的、更易于管理的部分。这有助于提高查询性能，并简化数据管理。