Oracle基础学习四:字符串 数字 日期 等 相关函数

以下内容摘自
Oracle PL/SQL Programming(By Steven Feuerstein, Bill Pribyl)
本人并没有逐个学习每个函数的功能及其用法
有兴趣或有用到的话  请自行掌握
A. String
B. Number
C. Dates and Times
=========================
A. String :
===========
01. ASCII(single_character)
02. ASCIISTR(string1)
03. CHR(code_location)
04. COMPOSE(string1)
05. CONCAT(string1, string2)
06. CONVERT(string1, target_char_set)
07. DECOMPOSE(string1)
08. GREATEST(string1, string2, ...)
09. INITCAP(string1)
10. INSTR(string1, string2)
11. LEAST(string1, string2, ...)
12. LENGTH(string1)
13. LOWER(string1)
14. LPAD(string1, padded_length)
15. LTRIM(string1)
16. NCHR(code_location)
17. NLS_INITCAP(string1)
18. NLS_LOWER(string1) and NLS_LOWER(string1, 'NLS_SORT=sort_sequence_name')
19. NLS_UPPER(string1) and NLS_UPPER(string1, 'NLS_SORT=sort_sequence_name')
20. NLSSORT(string1) and NLSSORT(string1, 'NLS_SORT=sort_sequence_name')
21. REPLACE(string1, match_string, replace_string)
22. RPAD(string1, padded_length)
23. RTRIM(string1)
24. SOUNDEX(string1)
25. SUBSTR(string1, start, length)
26. TO_CHAR(national_character_data)
27. TO_MULTI_BYTE(string1)
28. TO_NCHAR(database_character_data)
29. TO_SINGLE_BYTE(string1)
30. TRANSLATE (string1, search_set, replace_set)
31. TRANSLATE(text USING CHAR_CS) and TRANSLATE(text USING NCHAR_CS)
32. TRIM (FROM string1)
33. UNISTR(string1)
34. UPPER(string1)
示例
SQL> SELECT LENGTH(TRIM('AAA   ')) VALUE FROM DUAL
  2  ;
     VALUE
----------
         3
===========
B. Number :
===========
01. ABS(n)
02. ACOS(n)
03. ASIN(n)
04. ATAN(n)
05. ATAN2(n, m)
06. BIN_TO_NUM(b1, b2,...bn)
07. BITAND(n, m)
08. CEIL(n)
09. COS(n)
10. COSH(n)
11. EXP(n)
12. FLOOR(n)
13. GREATEST(n1, n2,...n3)
14. LEAST(n1, n2,...n3)
15. LN(n)
16. LOG(b, n)
17. MOD(n, m)
18. NANVL(n, m)
19. POWER(n, m)
20. REMAINDER(n, m)
21. ROUND(n)
22. ROUND(n, m)
23. SIGN(n)
24. SIN(n)
25. SINH(n)
26. SQRT(n)
27. TAN(n)
28. TANH(n)
29. TRUNC(n)
30. TRUNC(n, m)
示例
SQL> SELECT POWER(4,2) AS VALUE FROM DUAL;
     VALUE
----------
        16
====================
C. Dates and Times :
====================
01. ADD_MONTHS
02. CAST
03. CURRENT_DATE
04. CURRENT_TIMESTAMP
05. DBTIMEZONE
06. EXTRACT
07. FROM_TZ
08. LAST_DAY
09. LOCALTIMESTAMP
10. MONTHS_ BETWEEN
11. NEW_TIME
12. NEXT_DAY
13. NUMTODSINTERVAL
14. NUMTOYMINTERAL
15. ROUND
16. SESSIONTIMEZONE
17. SYSDATE
18. SYS_EXTRACT_UTC
19. SYSTIMESTAMP
20. TO_CHAR
21. TO_DATE
22. TO_DSINTERVAL
23. TO_TIMESTAMP
24. TO_TIMESTAMP_TZ
26. TO_YMINTERVAL
27. TRUNC
28. TZ_OFFSET
示例
SQL> SET SERVEROUTPUT ON
SQL> DECLARE
  2         current_date DATE;
  3         next_month DATE;
  4      BEGIN
  5         current_date := SYSDATE;
  6         next_month := ADD_MONTHS(current_date, 1);
  7         DBMS_OUTPUT.PUT_LINE(next_month);
  8      END;
  9  /
16-5月 -07
PL/SQL 过程已成功完成。
-----------------------------------

EXTRACT (component_name, FROM {datetime | interval})
Datetime component names for use with EXTRACT
01. YEAR
02. MONTH
03. DAY
04. HOUR
05. MINUTE
06. SECOND
07. TIMEZONE_HOUR
08. TIMEZONE_MINUTE
09. TIMEZONE_REGION
10. TIMEZONE_ABBR
示例
SQL> BEGIN
  2         IF EXTRACT (MONTH FROM SYSDATE) = 11 THEN
  3            DBMS_OUTPUT.PUT_LINE('It is November');
  4         ELSE
  5            DBMS_OUTPUT.PUT_LINE('It is not November');
  6         END IF;
  7      END;
  8  /
It is not November
PL/SQL 过程已成功完成。