INFORMIX 时间函数大全

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List of Expressions

Each category of SQL expression includes many individual expressions. The following table lists all the SQL expressions (and some operators) in alphabetical order. The columns in this table have the following meanings:

• Name gives the name of each expression.
• Description gives a short description of each expression.
• Syntax lists the page that shows the syntax of the expression.
• Usage shows the page that describes the usage of the expression.

Each expression listed in the following table is supported on all database servers unless otherwise noted. When an expression is not supported on all database servers, the Name column notes in parentheses the database server or servers that do support the expression.

Name	Description	Syntax	Usage
ABS function	Returns absolute value of a numeric argument	Algebraic Functions	ABS Function
ACOS function	Returns the arc cosine of a numeric argument	Trigonometric Functions	ACOS Function
ADD_MONTHS function	Adds a specified number of months	Time Functions	ADD_MONTHS Function
Addition ( + ) operator	Returns the sum of two numeric operands	Expression	Arithmetic Operators
ASCII function	Returns the ASCII codepoint of the first character in its string argument	String-Manipulation Functions	ASCII Function
ASIN function	Returns the arc sine of a numeric argument	Trigonometric Functions	ASIN Function
ATAN function	Returns the arc tangent of numeric argument	Trigonometric Functions	ATAN Function
ATAN2 function	Computes the angular component of the polar coordinates (r, q) associated with (x, y)	Trigonometric Functions	ATAN2 Function
AVG function	Returns the mean of a set of numeric values	Aggregate Expressions	AVG Function
BITAND	Returns the bitwise AND of two arguments	Bitwise Logical Functions	BITAND Function
BITANDNOT	Returns the bitwise ANDNOT of two arguments	Bitwise Logical Functions	BITANDNOT Function
BITNOT	Returns the bitwise NOT of two arguments	Bitwise Logical Functions	BITNOT Function
BITOR	Returns the bitwise OR of two arguments	Bitwise Logical Functions	BITOR Function
BITXOR	Returns the bitwise XOR of two arguments	Bitwise Logical Functions	BITXOR Function
CARDINALITY function (IDS)	Returns the number of elements in a collection data type (SET, MULTISET, or LIST)	CARDINALITY Function (IDS)	CARDINALITY Function (IDS)
CASE expression	Returns a value that depends on which of several conditional tests evaluates to true	CASE Expressions	CASE Expressions
CAST expression (IDS)	Converts an expression to a specified data type	Cast Expressions (IDS)	Cast Expressions (IDS)
Cast ( :: ) operator	See "Double-colon ( :: ) cast operator"	Cast Expressions (IDS)	Cast Expressions (IDS)
CEIL function	Returns the smallest integer that is greater than or equal to its single argument	Algebraic Functions	CEIL Function
CHARACTER_ LENGTH function	See CHAR_LENGTH function. (In multibyte locales, this replaces the LENGTH function.)	Length Functions	CHAR_LENGTH Function
CHAR_LENGTH function	Returns count of logical characters in a string	Length Functions	CHAR_LENGTH Function
Column expression	Complete or partial column value from a table	Column Expressions	Column Expressions
CONCAT( ) operator function	Concatenates the results of two expressions	String-Manipulation Functions	CONCAT Function
Concatenation ( || ) operator	Concatenates the results of two expressions	Expression	Concatenation Operator
Constant expression	Expression with a literal, fixed, or variant value	Constant Expressions	Constant Expressions
COS function	Returns the cosine of a radian expression	Trigonometric Functions	COS Function
COUNT (as a set of functions)	Functions that return frequency counts Each form of the COUNT function is listed below.	Aggregate Expressions	Overview of COUNT Functions
COUNT (ALL column) function	See COUNT (column) function.	Aggregate Expressions	COUNT column Function
COUNT (column) function	Returns the number of non-NULL values in a specified column	Aggregate Expressions	COUNT column Function
COUNT DISTINCT function	Returns the number of unique non-NULL values in a specified column	Aggregate Expressions	COUNT DISTINCT and COUNT UNIQUE Functions
COUNT UNIQUE function	See COUNT DISTINCT function.	Aggregate Expressions	COUNT DISTINCT and COUNT UNIQUE Functions
COUNT (*) function	Returns the cardinality of the set of rows that satisfy a query	Aggregate Expressions	COUNT(*) Function
CURRENT operator	Returns the current time as a DATETIME value that consists of the date and the time of day	Constant Expressions	CURRENT Operator
CURRENT_ROLE operator	Returns the currently enabled role of the user	Constant Expressions	CURRENT_ROLE Operator
sequence.CURRVAL (IDS)	Returns the current value of specified sequence	Constant Expressions	Using CURRVAL
DATE function	Converts a nondate argument to a DATE value	Time Functions	DATE Function
DAY function	Returns the day of the month as an integer	Time Functions	DAY Function
DBINFO (option)	Functions for retrieving database and session information. Each option is listed below.	DBINFO Function	DBINFO Options
DBINFO ('bigserial')	Returns most recently inserted BIGSERIAL value	DBINFO Function	Using the 'serial8' Option and 'bigserial' Option
DBINFO ('serial8')	Returns most recently inserted SERIAL8 value	DBINFO Function	Using the 'serial8' Option and 'bigserial' Option
DBINFO ('coserverid', table. column, 'currentrow') (XPS)	Returns the coserver ID of the coserver where each row of a specified table is located	DBINFO Function	Using the 'coserverid' Option Followed by Table and Column Names (XPS)
DBINFO ('coserverid') (XPS)	Returns the coserver ID of the coserver to which the user who entered the query is connected	DBINFO Function	Using the 'coserverid' Option with No Other Arguments (XPS)
DBINFO ('dbhostname')	Returns the host name of the database server to which a client application is connected	DBINFO Function	Using the ‘dbhostname’ Option
DBINFO ('dbname')	Returns the identifier of the database to which a client application is connected	DBINFO Function	Using the ‘dbname' Option
DBINFO ('dbspace', table.column, 'currentrow') (XPS)	Returns the name of the dbspace where each row of a specified table is located	DBINFO Function	Using the 'dbspace' Option Followed by Table and Column Names (XPS)
DBINFO ('dbspace', tblspace_number)	Returns the name of a dbspace corresponding to a tblspace number	DBINFO Function	Using the ('dbspace', tblspace_num) Option
DBINFO ('get_tz' )	Returns the time zone of the current session	DBINFO Function	Using the 'get_tz' Option
DBINFO ('serial8')	Returns most recently inserted SERIAL8 value	DBINFO Function	Using the 'serial8' Option and 'bigserial' Option
DBINFO ('sessionid')	Returns the session ID of the current session	DBINFO Function	Using the 'sessionid' Option
DBINFO ('sqlca.sqlerrd1')	Returns the last serial value inserted in a table	DBINFO Function	Using the 'sqlca.sqlerrd1' Option
DBINFO ('sqlca.sqlerrd2')	Returns the number of rows processed by DML statements, and by EXECUTE PROCEDURE and EXECUTE FUNCTION statements	DBINFO Function	Using the 'sqlca.sqlerrd2' Option
DBINFO ('utc_current')	Returns the current Coordinated Universal Time (UTC) value.	DBINFO Function	Using the 'utc_current' Option
DBINFO ('utc_to_datetime', expression)	Returns the DATETIME value of an integer or column expression that specifies a UTC value.	DBINFO Function	Using the 'utc_to_datetime' Option
DBINFO ('version', parameter)	Returns all or part, as specified by the parameter, of the exact version of the database server to which the client application is connected.	DBINFO Function	Using the ‘version' Option
DBSERVERNAME function	Returns the name of the database server	Constant Expressions	DBSERVERNAME and SITENAME Operators
DECODE function	Evaluates one or more expression pairs and compares the when expression in each pair with a specified value expression	DECODE Function	DECODE Function
DECRYPT_CHAR function (IDS)	Returns a plain-text string or CLOB after processing an encrypted argument	Encryption and Decryption Functions	DECRYPT_CHAR Function
DECRYPT_ BINARY function (IDS)	Returns a plain-text BLOB data value after processing an encrypted BLOB argument	Encryption and Decryption Functions	DECRYPT_BINARY Function
DEFAULT_ROLE operator	Returns the default role of the current user	Constant Expressions	DEFAULT_ROLE Operator
DELETING Boolean operator	Returns 't' if triggering event is a DELETE	Trigger-Type Boolean Operator	Trigger-Type Boolean Operator
Division ( / ) operator	Returns the quotient of two numeric operands	Expression	Arithmetic Operators
Double-colon ( :: ) cast operator (IDS)	Converts the value of an expression to a specified data type	Cast Expressions (IDS)	Cast Expressions (IDS)
Double-pipe ( || ) concatenation operator	Returns a string that joins one string operand to another string operand	Expression	Concatenation Operator
ENCRYPT_AES function (IDS)	Returns an encrypted string or BLOB after processing a plain-text string, BLOB, or CLOB	Encryption and Decryption Functions	ENCRYPT_AES Function
ENCRYPT_TDES function (IDS)	Returns an encrypted string or BLOB after processing a plain-text string, BLOB, or CLOB	Encryption and Decryption Functions	ENCRYPT_TDES Function
EXP function	Returns the exponent of a numeric expression	Exponential and Logarithmic Functions	EXP Function
EXTEND function	Resets precision of DATETIME or DATE value	Time Functions	EXTEND Function
FILETOBLOB function (IDS)	Creates a BLOB value from data stored in a specified operating-system file	Smart-Large-Object Functions (IDS)	FILETOBLOB and FILETOCLOB Functions
FILETOCLOB function (IDS)	Creates a CLOB value from data stored in a specified operating-system file	Smart-Large-Object Functions (IDS)	FILETOBLOB and FILETOCLOB Functions
FLOOR function	Returns the largest integer that is smaller than or equal to its single argument	Algebraic Functions	FLOOR Function
FORMAT_UNITS function	Returns a character string that specifies a number and the names of abbreviated units of memory or of storage	FORMAT_UNITS Function	FORMAT_UNITS Function
GETHINT function (IDS)	Returns a plain-text hint string after processing an encrypted data-string argument	Encryption and Decryption Functions	GETHINT Function
HEX function	Returns the hexadecimal encoding of a base-10 integer argument	HEX Function	HEX Function
Host variable	See Variable.	Syntax of SQL Expressions	Syntax of SQL Expressions
INSERTING Boolean operator	Returns 't' if triggering event is an INSERT	Trigger-Type Boolean Operator	Trigger-Type Boolean Operator
IFX_ALLOW_ NEWLINE function	Sets a newline session mode that allows or disallows newline characters in quoted strings	IFX_ALLOW_NEWLINE Function	IFX_ALLOW_NEWLINE Function
INITCAP function	Converts a string argument to a string in which only the initial letter of each word is uppercase	Case-Conversion Functions	INITCAP Function
LAST_DAY function	Returns the date of the last day of the month that its argument specifies	Time Functions	LAST_DAY Function
LENGTH function	Returns the number of bytes in a character column, not including any trailing blank spaces	Length Functions	LENGTH Function
LIST collection constructor (IDS)	Constructor for collections whose elements are ordered and can contain duplicate values	Collection Constructors	Collection Constructors
Literal BOOLEAN	Literal representation of a BOOLEAN value	Constant Expressions	Constant Expressions
Literal collection (IDS)	Represents elements in a collection data type	Constant Expressions	Literal Collection (IDS)
Literal DATETIME	Represents a DATETIME value	Constant Expressions	Literal DATETIME
Literal INTERVAL	Represents an INTERVAL value	Constant Expressions	Literal INTERVAL
Literal number	Represents a numeric value	Constant Expressions	Literal Number
Literal opaque type (IDS)	Represents an opaque data type	Constant Expressions	Constant Expressions
Literal row (IDS)	Represents the elements in a ROW data type	Constant Expressions	Literal Row (IDS)
LOCOPY function (IDS)	Creates a copy of a smart large object	Smart-Large-Object Functions (IDS)	LOCOPY Function
LOGN function	Returns the natural log of a numeric argument	Exponential and Logarithmic Functions	LOGN Function
LOG10 function	Returns the base-10 logarithm of an argument	Exponential and Logarithmic Functions	LOG10 Function
LOTOFILE function (IDS)	Copies a BLOB or CLOB value to a file	Smart-Large-Object Functions (IDS)	LOTOFILE Function
LOWER function	Converts uppercase letters to lowercase	Case-Conversion Functions	LOWER Function
LPAD function	Returns a string that is left-padded by a specified number of pad characters	String-Manipulation Functions	LPAD Function
LTRIM function	Removes specified leading pad characters from a string.	String-Manipulation Functions	LTRIM Function
MAX function	Returns the largest in a specified set of values	Aggregate Expressions	MAX Function
MDY function	Returns a DATE value from integer arguments	Time Functions	MDY Function
MIN function	Returns the smallest in a specified set of values	Aggregate Expressions	MIN Function
MOD function	Returns the modulus (the integer-division remainder value) from two numeric arguments	Algebraic Functions	MOD Function
MONTH function	Returns the month value from a DATE or DATETIME argument	Time Functions	MONTH Function
MONTHS_ BETWEEN function	Returns the difference in months between two time values	Time Functions	MONTHS_BETWEEN Function
Multiplication ( * ) operator	Returns the product of two numeric operands	Expression	Arithmetic Operators
MULTISET collection constructor (IDS)	Constructor for a non-ordered collection of elements that can contain duplicate value	Collection Constructors	Collection Constructors
NEXT_DAY function	Returns the earliest calendar date that satisfies each of two conditions	Time Functions	NEXT_DAY Function
sequence.NEXTVAL (IDS)	Increments value of the specified sequence	Constant Expressions	Using NEXTVAL
NULL keyword	Unknown, missing, or logically undefined value	NULL Keyword	NULL Keyword
NULLIF function	Returns NULL if both arguments are equal	NULLIF Function	NULLIF Function
NVL function	Returns the value of a not-NULL argument, or a specified value if the argument is NULL	NVL Function	NVL Function
OCTET_LENGTH function	Returns the number of bytes in a character column, including any trailing blank spaces	Length Functions	OCTET_LENGTH Function
POW function	Raises a base value to a specified power	Algebraic Functions	POW Function
POWER function	Synonym for POW function	Algebraic Functions	POW Function
Procedure-call expression	See user-defined function.	User-Defined Functions	User-Defined Functions
Program variable	See variable.	Syntax of SQL Expressions	Syntax of SQL Expressions
Quoted string	Literal character string	Constant Expressions	Quoted String
RANGE function	Returns the range of a specified set of values	Aggregate Expressions	RANGE Function
REPLACE function	Replaces specified characters in a source string	String-Manipulation Functions	REPLACE Function
ROOT function	Returns the root value of a numeric argument	Algebraic Functions	ROOT Function
ROUND function	Returns the rounded value of an argument	Algebraic Functions	ROUND Function
ROW constructor (IDS)	Constructor for a named ROW data type	Constructor Expressions (IDS)	ROW Constructors
RPAD function	Returns a string that is right-padded by a specified number of pad characters	String-Manipulation Functions	RPAD Function
RTRIM function	Removes trailing pad characters from a string	String-Manipulation Functions	RTRIM Function
SECLABEL_BY_ COMP function	Returns the individual components of a row security label for INSERT and UPDATE operations	Security Label Support Functions (IDS)	SECLABEL_BY_NAME Function
SECLABEL_BY_ NAME function	Returns the identifier of a row security label for INSERT and UPDATE operations	Security Label Support Functions (IDS)	SECLABEL_BY_COMP Function
SECLABEL_TO_ CHAR function	Returns the details of the individual components of a row security label for SELECT operations	Security Label Support Functions (IDS)	SECLABEL_TO_CHAR Function
SELECTING Boolean operator	Returns 't' if triggering event is a SELECT	Trigger-Type Boolean Operator	Trigger-Type Boolean Operator
SET collection constructor (IDS)	Constructor for an unordered collection of elements in which each value is unique	Collection Constructors	Collection Constructors
SIN function	Returns the sine of a radian expression	Trigonometric Functions	SIN Function
SITENAME function	See DBSERVERNAME function.	Constant Expressions	DBSERVERNAME and SITENAME Operators
SPL routine expression	See "User-defined functions"	User-Defined Functions	User-Defined Functions
SPL variable	SPL variable that stores an expression	Syntax of SQL Expressions	Syntax of SQL Expressions
SQLCODE function	Returns sqlca.sqlcode value to an SPL UDR	SQLCODE Function (SPL)	SQLCODE Function (SPL)
SQRT function	Returns the square root of a numeric argument	Algebraic Functions	SQRT Function
STDEV function	Returns the standard deviation of a data set	Aggregate Expressions	STDEV Function
SUBSTR function	Returns a substring of a string argument	SUBSTR Function	SUBSTR Function
SUBSTRING function	Returns a substring of a source string	SUBSTRING Function	SUBSTRING Function
Substring ( [ x, y ] ) operator	Returns a substring of a string operand	Column Expressions	Using the Substring Operator
Subtraction ( - ) operator	Returns the difference between two numbers	Expression	Arithmetic Operators
SUM function	Returns the sum of a specified set of values	Aggregate Expressions	SUM Function
SLV expression	A statement-local variable (SLV) whose scope is the SQL statement that declares it	Statement-Local Variable Declaration (IDS)	Statement-Local Variable Expressions (IDS)
SYSDATE operator	Returns the current DATETIME value from the system clock.	Constant Expressions	SYSDATE Operator
TAN function	Returns the tangent of a radian expression	Trigonometric Functions	TAN Function
TO_CHAR function	Converts a time or number to a string	Time Functions	TO_CHAR Function (IDS)
TO_DATE function	Converts a string to a DATETIME value	Time Functions	TO_DATE Function (IDS)
TO_NUMBER function	Converts two numbers or two strings to DECIMAL	TO_NUMBER Function	TO_NUMBER Function
TODAY operator	Returns the current system date	Constant Expressions	TODAY Operator
TRIM function	Drops pad characters from a string argument	String-Manipulation Functions	TRIM Function
TRUNC function	Returns a truncated numeric or time value	Algebraic Functions	TRUNC Function
Unary minus ( - ) sign	Specifies a negative ( < 0 ) numeric value	Expression	Arithmetic Operators
Unary plus ( + ) sign	Specifies a positive ( > 0 ) numeric value .	Expression	Arithmetic Operators
UNITS operator	Convert an integer to an INTERVAL value	Constant Expressions	UNITS Operator
UPDATING Boolean operator	Returns 't' if triggering event is an UPDATE	Trigger-Type Boolean Operator	Trigger-Type Boolean Operator
UPPER function	Converts lowercase letters to uppercase	Case-Conversion Functions	UPPER Function
User-defined aggregate (IDS)	Aggregate that you define (as opposed to built-in aggregates that Dynamic Server provides)	User-Defined Aggregates (IDS)	User-Defined Aggregates (IDS)
User-defined function	Function that you write (as opposed to built-in functions that the database server provides)	User-Defined Functions	User-Defined Functions
USER operator	Returns the login name of the current user	Constant Expressions	USER Operator
Variable	Host or program variable that stores a value	Syntax of SQL Expressions	Syntax of SQL Expressions
VARIANCE function	Returns the variance for a set of values	Aggregate Expressions	VARIANCE Function
WEEKDAY function	Returns an integer code for the day of the week	Time Functions	WEEKDAY Function
YEAR function	Returns a 4-digit integer representing a year	Time Functions	YEAR Function
* symbol	See "Multiplication ( * ) operator"	Syntax of SQL Expressions	Arithmetic Operators
+ symbol	See "Addition" and "Unary plus ( + ) sign"	Syntax of SQL Expressions	Arithmetic Operators
- symbol	See "Subtraction" and "Unary minus ( - ) sign"	Syntax of SQL Expressions	Arithmetic Operators
/ symbol	See "Division operator"	Syntax of SQL Expressions	Arithmetic Operators
:: symbols	See "Double-colon ( :: ) cast operator"	Cast Expressions (IDS)	Cast Expressions (IDS)
|| symbol	See "Double-pipe ( || ) concatenation operator"	Syntax of SQL Expressions	Concatenation Operator
[ first, last ] symbols	See "Substring operator"	Column Expressions	Using the Substring Operator

Sections that follow describe the syntax and usage of each expression that appears in the preceding table.

Parent topic: Expression

Related reference

Syntax of SQL Expressions

Usage

Arithmetic Operators

Bitwise Logical Functions

Concatenation Operator

Cast Expressions (IDS)

Column Expressions

Conditional Expressions

Constant Expressions

Constructor Expressions (IDS)

NULL Keyword

Function Expressions

Statement-Local Variable Expressions (IDS)

Aggregate Expressions