String: Concat (Char1, Char2); Returns the results connected to Charl and Char2.
INITCAP (Char): turn the first letter of each word in char to uppercase and returns.
Lower / Upper (Char); turn all letters of char to small / uppercase and return
LPAD (Charl.n, [Char2]) / RPAD (CHAR1, N [, Char2]): Plus the Char2 character sequence in the left / right side of Charl until the newly generated string total length is N, then return to new String, the default value of char2 is a single space
Ltrim (char [, set]): Remove the letters belonging to the set character set from the left / right side of Char until the first one does not belong to the character, returns a new string. The set default is space.
Replace (CHAR, Search_String]): Use replacement_string to replace all strings Search_String in Char, if Replacement_String is omitted, remove all Search_String.
Substr (Char, M [, N]): From the first m characters of char to take n characters, constitute a substring of char and return
Length (char): Returns the length of the string
date:
Add_MONTHS (D, N): Calculate the date D plus N month date and return
Last_Day (d): Returns the date corresponding to the last day of the month of the date D
MONTHS_BETWEEN (D1, D2): The number of months between the calculation d1 and d2
D1 later than D2,
D1 earlier than D2,
Equal, return to an integer
Trunc (D, [FMT]): Cut the date D and return it according to the unit specified in the format mode FMT.
Numerical:
Trunc (N [, M]): Returns the n value truncated in the M bit, when M omit is omitted, at the 0-bit truncation, when the M is negative, cutting the left M digits of the decimal point.
Conversion function:
TO_CHAR (D [, FMT [, 'NLSPARAMS']]: Convert D by the date type value into a VARCHAR2 type according to the date format specified by the FMT
The date format specified by FMT should be enclosed in single quotes.
TO_DATE (CHAR [, FMT [, 'NLSPARAMS']]): Convert CHAR by the CHAR or VARCHAR2 type to date type value according to the date format specified by FMT
TO_NUMBER (CHAR [, FMT, ['NLSPARAMS]]: Convert Char by CHAR type or varchar2 type to numeric type data
Miscellaneous function:
Dump (expr, [, return_format [, start_position [, length]]:
GreateSt (expr [, expr] *) / Least: Returns the maximum / small value in all EXPR expressions. Quask in the type of the first expression
NVL (Expr1, Expr2): If the value of expression expr1 is empty, return the value of Express EXPR2, if expression expr1 is not empty, return the value of the value of the expression EXPR1
Count (<* | [DISTINCT | All] expr>)
MIN ([Distinct | All] EXPR)
Max ([DISTINCT | All] EXPR)
AVG ([Distinct | all] n)
SUM ([Distinct | All] n)
