# Comparison between SQL Server and common Oracle Functions

Source: Internet
Author: User

Mathematical functions

1. Absolute Value

S: Select ABS (-1) Value

O: Select ABS (-1) value from dual

2. INTEGER (large)

S: Select ceiling (-1.001) Value

O: Select Ceil (-1.001) value from dual

3. Round (small)

S: Select floor (-1.001) Value

O: Select floor (-1.001) value from dual

4. Round (truncation)

S: Select cast (-1.002 as INT) Value

O: Select trunc (-1.002) value from dual

5. Rounding

S: Select round (1.23456, 4) value 1.23460

O: Select round (1.23456, 4) value from dual 1.2346

6. e is the base power

S: Select exp (1) Value 2.7182818284590451

O: Select exp (1) value from dual 2.71828182

7. Take the base logarithm of E.

S: Select log (1, 2.7182818284590451) value 1

O: Select Ln (2.7182818284590451) value from dual; 1

8. Use 10 as the base logarithm.

S: Select log10 (10) value 1

O: select log (10, 10) value from dual; 1

9. Square

S: select SQUARE (4) value 16

O: select power (4, 2) value from dual 16

10. Take the square root

S: select SQRT (4) value 2

O: select SQRT (4) value from dual 2

11. Evaluate the base power of any number

S: select power (3, 4) value 81

O: select power (3, 4) value from dual 81

12. Random Number acquisition

S: select rand () value

O: select sys. dbms_random.value (0, 1) value from dual;

13. Get the symbol

S: select sign (-8) value-1

O: select sign (-8) value from dual-1

14. Circumference Rate

S: select pi () value 3.1415926535897931

O: Unknown

15. sin, cos, and tan parameters are in radians.

For example, select sin (PI ()/2) value to get 1 (SQLServer)

16. Asin, Acos, Atan, Atan2 return radians

17. radian angle Interchange (, Oracle unknown)

Comparison between values

18. Calculate the maximum value of the Set

S: select max (value) value from

(Select 1 value

Union

Select-2 value

Union

Select 4 value

Union

Select 3 value)

O: select greatest (1,-2, 4, 3) value from dual

19. Minimum value of the Set

S: select min (value) value from

(Select 1 value

Union

Select-2 value

Union

Select 4 value

Union

Select 3 value)

O: select least (1,-2, 4, 3) value from dual

20. How to Handle null values (replace null with 10 in F2)

S: select F1, IsNull (F2, 10) value from Tbl

O: select F1, nvl (F2, 10) value from Tbl

21. Search for the character serial number

S: select ascii ('A') value

O: select ascii ('A') value from dual

22. calculate characters from the serial number

S: select char (97) value

O: select chr (97) value from dual

23. Connection

S: select '11' + '22' + '33' value

O: select CONCAT ('11', '22') 33 value from dual

23. substring position -- return 3

S: select CHARINDEX ('s ', 'sdsq', 2) value

O: select INSTR ('sdsq', 's', 2) value from dual

23. Position of the fuzzy substring -- 2 is returned. If % is removed from the parameter, 7 is returned.

S: select patindex ('% d % q %', 'sdsfasdqe ') value

O: no oracle found, but instr can use the fourth parameter to control the number of occurrences.

Select INSTR ('sdsfasdqe ', 'sd', 1, 2) value from dual returns 6

24. Seek substrings

S: select substring ('abcd', 2, 2) value

O: select substr ('abc', 2, 2) value from dual

25. Return aijklmnef as a substring

S: select stuff ('abcdef', 2, 3, 'ijklmn ') value

O: SELECT Replace ('abcdef', 'bcd', 'ijklmn ') value from dual

26. replace all substrings

S: No

O: Select translate ('fasdbfasegas', 'fa ', 'my') value from dual

27. Length

S: Len, datalength

O: Length

28. case-insensitive lower, upper

29. uppercase letters

S: No

O: Select initcap ('abcd DSAF df') value from dual

30. Left fill space (the first parameter of lpad is space, which is the same as the space function)

S: Select space (10) + 'abc' Value

O: Select lpad ('abc', 14) value from dual

31. Right fill space (the first parameter of rpad is space, which is the same as the space function)

S: Select 'abc' + space (10) Value

O: Select rpad ('abcd', 14) value from dual

32. Delete Spaces

S: ltrim, rtrim

O: ltrim, rtrim, trim

33. Duplicate string

S: Select replicate ('abcd', 2) Value

O: No

34. Comparison of pronunciation similarity (the two words return the same value and have the same pronunciation)

S: Select soundex ('Smith '), soundex ('smy ')

O: Select soundex ('Smith '), soundex ('smy') from dual

Comparison of soundex with select difference ('smithers', 'smythers ') in sqlserver

Returns 0-4, 4 for homophone, 1 for maximum

Date Functions

35. system time

S: Select getdate () Value

O: Select sysdate value from dual

36. days before and after

Directly add or subtract from an integer

37. Calculate the date

S: Select convert (char (10), getdate (), 20) Value

O: Select trunc (sysdate) value from dual

Select to_char (sysdate, 'yyyy-mm-dd') value from dual

38. Time

S: Select convert (char (8), getdate (), 108) Value

O: Select to_char (sysdate, 'hh24: mm: ss') value from dual

39. Take other parts of date and time

S: datepart and datename functions (determined by the first parameter)

O: The second parameter of the to_char function is determined.

Parameter ---- The following table needs to be supplemented

Year YY, yyyy

Quarter QQ, Q (quarter)

Month mm, M (m o is invalid)

Dayofyear dy, y (O table week)

Day dd, d (d O is invalid)

Week wk, ww (wk O is invalid)

Weekday dw (unclear O)

Hour hh, hh12, hh24 (hh12, hh24 S is invalid)

Minute mi, n (n O is invalid)

Second ss, s (s O is invalid)

Millisecond MS (invalid O)

--------------------------------------

40. Last day of the month

S: Unknown

O: select LAST_DAY (sysdate) value from dual

41. A day of the week (such as Sunday)

S: Unknown

O: SELECT Next_day (sysdate, 7) vaule from dual;

42. String Conversion time

S: Can be directly converted to or select cast ('2017-09-08 'as datetime) value

O: SELECT To_date ('2017-01-05 22:09:38 ', 'yyyy-mm-dd hh24-mi-ss') vaule from dual;

43. Calculate the difference of a part of the two dates (for example, seconds)

S: select datediff (ss, getdate (), getdate () + 12.3) value

O: Subtract directly with two dates (for example, d1-d2 = 12.3)

Select (d1-d2) * 24*60*60 vaule from dual;

44. Calculate a new date (for example, minute) based on the difference value)

S: Select dateadd (MI, 8, getdate () Value

O: Select sysdate + 8/60/24 vaule from dual;

45. Time in different time zones

S: Unknown

O: Select new_time (sysdate, 'ydt ', 'gmt') vaule from dual;

----- Time Zone parameter. Beijing must be in the east 8 zone of ydt -------

Bst bdt Standard Time

Standard Time for central CST CDT

Est EDT standard Eastern Time

GMT Standard Time

Hst hdt Alaska? Hawaii Standard Time

Standard Time for mst mdt Mountainous Areas

NST standard time for new Finland

Pst PDT Pacific Standard Time

Yst ydt Yukon Standard Time

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