Time Series Database:TSQL functions

Aggregate functions

Mathematical functions

TSQL supports the mathematical functions that are described in the following table and the trigonometric functions that are listed in the "Trigonometric functions" section. Most mathematical functions and all trigonometric functions support input values of the following data types:

• INTEGER

• BIGINT

• FLOAT

• DOUBLE

• SMALLINT

Examples

The math_func_demo table is used in the following examples of mathematical functions. The math_func_demo table contains the following data:

select * from math_func_demo;

+---------------+-----------------------+
|    integer    |         float         |
+---------------+-----------------------+
|2010|17.4|
|-2002|-1.2|
|2001|1.2|
|6005|1.2|
+---------------+-----------------------+

• ABS(x)

  SELECT ABS(`integer`) FROM math_func_demo;
  +------------+
  |   EXPR$0   |
  +------------+
  | 2010       |
  | 2002       |
  | 2001       |
  | 6005       |
  +------------+
  4 rows selected (0.357 seconds)

• CEIL(x)

  SELECT CEIL(`float`) FROM math_func_demo;
  +------------+
  |   EXPR$0   |
  +------------+
  | 18.0       |
  | -1.0       |
  | 2.0        |
  | 2.0        |
  +------------+
  4 rows selected (0.647 seconds)

• FLOOR(x)

  SELECT FLOOR(`float`) FROM math_func_demo;
  +------------+
  |   EXPR$0   |
  +------------+
  | 17.0       |
  | -2.0       |
  | 1.0        |
  | 1.0        |
  +------------+
  4 rows selected (0.11 seconds)

• ROUND(x) and ROUND(x, y): The ROUND(x) function example returns the nearest integer. The Round (x, y) function example returns an approximate number that is rounded to four decimal places.

  ``bash
  SELECT ROUND(float`) FROM math_func_demo;
  +------------+
  | EXPR$0     |
  +------------+
  | 3.0        |
  | -1.0       |
  | 1.0        |
  | 1.0        |
  +------------+
  4 rows selected (0.061 seconds)
  SELECT ROUND(float, 4) FROM math_func_demo;
  +------------+
  | EXPR$0 |
  +------------+
  | 3.1416     |
  | -1.2       |
  | 1.2        |
  | 1.2        |
  +------------+
  4 rows selected (0.059 seconds)

• LOG(x, y), LOG10(x), and LOG(x): The LOG(x, y) function example returns the logarithm of 64 to a base of 2. The LOG10(x) function example returns the logarithm of 100 to the base of 10. The LOG(x) function example returns the base e logarithm of 7.5.

  ```bash
  SELECT LOG(2, 64) FROM (VALUES(1));
  +------------+
  |   EXPR$0   |
  +------------+
  | 6.0        |
  +------------+
  1 row selected (0.069 seconds)
  SELECT LOG10(100) FROM (VALUES(1));
  +------------+
  |   EXPR$0   |
  +------------+
  | 2.0        |
  +------------+
  1 row selected (0.203 seconds)
  SELECT LOG(7.5) FROM (VALUES(1));
  +---------------------+
  |       EXPR$0        |
  +---------------------+
  | 2.0149030205422647  |
  +---------------------+
  1 row selected (0.139 seconds)

Trigonometric functions

TSQL supports the following trigonometric functions. These functions return results of the FLOAT8 data type.

• SIN(x) returns the sine of a number. The x parameter specifies the number.

• COS(x) returns the cosine of a number. The x parameter specifies the number.

• TAN(x) returns the tangent of a number. The x parameter specifies the number.

• ASIN(x) returns the arcsine of a number. The x parameter specifies the number.

• ACOS(x) returns the arccosine of a number. The x parameter specifies the number.

• ATAN(x) returns the arctangent of a number. The x parameter specifies the number.

• SINH(x) returns the hyperbolic sine of a number. The x parameter specifies the number.

• COSH(x) returns the hyperbolic cosine of a number. The x parameter specifies the number.

• TANH(x) returns the hyperbolic tangent of a number. The x parameter specifies the number.

Examples

SELECT RADIANS(30) AS Degrees FROM (VALUES(1));

+------------+
|Degrees|
+------------+
|0.7853981633974483|
+------------+
1 row selected (0.045 seconds)

SELECT SIN(0.7853981633974483) AS `Sine of 30 degrees` FROM (VALUES(1));

+-----------------------+
|Sine of 45 degrees   |
+-----------------------+
|0.7071067811865475|
+-----------------------+
1 row selected (0.059 seconds)

SELECT TAN(0.7853981633974483) AS `Tangent of 30 degrees` from (VALUES(1));

+-----------------------+
|Tangent of 45 degrees |
+-----------------------+
|0.9999999999999999|
+-----------------------+

String functions

The following table lists the string functions that are supported by TSQL.

Examples

• CONCAT

  Syntax: CONCAT(string [,string [, ...]]). This function concatenates strings.

  SELECT CONCAT('Drill',' ',1.0,' ','release') FROM (VALUES(1));
  
  +--------------------+
  |       EXPR$0       |
  +--------------------+
  |Drill1.0 release  |
  +--------------------+
  1 row selected (0.134 seconds)

• INITCAP

  Syntax: INITCAP(string). This function returns a string in which the first letter of each word is uppercase and all other letters are lowercase.

  SELECT INITCAP('china beijing') FROM (VALUES(1));
  
  +---------------------------+
  |          EXPR$0           |
  +---------------------------+
  |ChinaBeijing|
  +---------------------------+
  1 row selected (0.106 seconds)

• LENGTH

  Syntax: LENGTH(string [, encoding]). This function returns the number of characters in a string.

  SELECT LENGTH('Hangzhou') FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  |8|
  +------------+
  1 row selected (0.127 seconds)

• LOWER

  Syntax: LOWER(string). This function converts uppercase characters in a string to lowercase characters.

  SELECT LOWER('China Beijing') FROM (VALUES(1));
  
  +---------------+
  |    EXPR$0     |
  +---------------+
  | china beijing  |
  +---------------+
  1 row selected (0.103 seconds)

• LPAD

  Syntax: LPAD(string,length [, fill text]). This function left pads a string to a specified length by using spaces or a specified fill text. If the length of the result string after padding exceeds the specified length, the result string is truncated to the specified length.

  SELECT LPAD('hi',5,'xy') FROM (VALUES(1));
  
  +------------------------------+
  |            EXPR$0            |
  +------------------------------+
  | xyxhi                        |
  +------------------------------+
  1 row selected (0.132 seconds)

• LTRIM

  Syntax: LTRIM(string1, string2). This function removes specified characters from the left side of a string. The string1 parameter specifies the source string from which you want to remove characters. The string2 parameter specifies the characters that you want to remove.

  SELECT LTRIM('zzzytest','xyz') FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  | test       |
  +------------+
  1 row selected (0.131 seconds)

• REGEXP_REPLACE

  Syntax: REGEXP_REPLACE(source_char, pattern, replacement). This function searches a string for a Java regular expression pattern and replaces each occurrence of the pattern with specified characters.

  SELECT REGEXP_REPLACE('abc, acd, ade, aef','a','b') FROM (VALUES(1));
  +---------------------+
  |       EXPR$0        |
  +---------------------+
  | bbc, bcd, bde, bef  |
  +---------------------+
  1 row selected (0.105 seconds)
  
  SELECT REGEXP_REPLACE('abc, acd, ade, aef','a.','b') FROM (VALUES(1));
  +-----------------+
  |     EXPR$0      |
  +-----------------+
  | bc, bd, be, bf  |
  +-----------------+
  1 row selected (0.113 seconds)

• RPAD

  Syntax: RPAD (string, length [, fill text]). This function right pads a string to a specified length by using spaces or a fill text. If you do not specify the fill text or the fill text cannot pad the string to the specified length, spaces are added to the end of the source string or the specified fill text to the specified length. If the length of the result string after padding exceeds the specified length, the result string is truncated to the specified length.

  SELECT RPAD('hi',5,'xy') FROM (VALUES(1));
  +-------------------------+
  |         EXPR$0          |
  +-------------------------+
  | hixyx                   |
  +-------------------------+
  1 row selected (0.107 seconds)

• RTRIM

  Syntax:RTRIM(string1, string2). This function removes specified characters from the right side of a string. The string1 parameter specifies the source string from which you want to remove characters. The string2 parameter specifies the characters that you want to remove.

  SELECT RTRIM('testxxzx','xyz')from(VALUES(1));
  +--------------------+
  |       EXPR$0       |
  +--------------------+
  | tes                |
  +--------------------+
  1 row selected (0.102 seconds)

• STRPOS

  Syntax: STRPOS(string, substring). This function returns the position of a substring in a string.

  SELECT STRPOS('high','ig') FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  |2|
  +------------+
  1 row selected (0.22 seconds)

• SUBSTR

  Syntax: SUBSTR(string, x, y). This function returns a substring of a string. The x parameter specifies the index of the first character that you want to include in the returned substring. The y parameter specifies the index of the last character that you want to include in the returned substring. The y parameter is optional.

  SELECT SUBSTR('China Beijing',7) FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  |Beijing|
  +------------+
  1 row selected (0.134 seconds)
  
  SELECT SUBSTR('China Beijing',3,2) FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  |in|
  +------------+
  1 row selected (0.129 seconds)

• TRIM

  Syntax: TRIM ([leading | trailing | both] [string1] from string2). This function removes specified characters from the left side, the right side, or both sides of a string. The string1 parameter specifies the string of characters that you want to remove. The string2 parameter specifies the source string.

  SELECT TRIM(trailing 'A'from'AABBAA') FROM (VALUES(1));
  +------------+
  |   EXPR$0   |
  +------------+
  | AABB       |
  +------------+
  1 row selected (0.172 seconds)
  
  SELECT TRIM(both 'A'from'AABBAA') FROM (VALUES(1));
  +---------------+
  |    EXPR$0     |
  +---------------+
  | BB            |
  +---------------+
  1 row selected (0.104 seconds)
  
  SELECT TRIM(leading 'A'from'AABBAA') FROM (VALUES(1));
  +-----------------+
  |     EXPR$0      |
  +-----------------+
  | BBAA            |
  +-----------------+
  1 row selected (0.101 seconds)

• UPPER

  Syntax: UPPER(string). This function converts lowercase characters in a string to uppercase characters.

  SELECT UPPER('china beijing') FROM (VALUES(1));
  
  +---------------+
  |    EXPR$0     |
  +---------------+
  | CHINA BEIJING |
  +---------------+
  1 row selected (0.081 seconds)

Timestamp functions

The following table lists the timestamp functions that are supported by TSQL.

The following statements provide examples on how to use the timestamp functions:

SELECT CURRENT_DATE FROM (VALUES(1));
+---------------+
| CURRENT_DATE  |
+---------------+
|2019-11-27|
+---------------+

SELECT EXTRACT(hour FROM TIME '17:12:28.5') FROM (VALUES(1));
+---------+
| EXPR$0  |
+---------+
|17|
+---------+

SELECT EXTRACT(SECOND FROM TIMESTAMP '2001-02-16 20:38:40') FROM (VALUES(1));
+---------+
| EXPR$0  |
+---------+
|40.0|
+---------+

SELECT DATE_DIFF(TIMESTAMP '2001-02-16 20:38:40', interval '5' minute) FROM (VALUES(1));
+------------------------+
|         EXPR$0         |
+------------------------+
|2001-02-1620:33:40.0|
+------------------------+

SELECT DATE_ADD(TIMESTAMP '2001-02-16 20:38:40', interval '5' minute) FROM (VALUES(1));
+------------------------+
|         EXPR$0         |
+------------------------+
|2001-02-1620:43:40.0|
+------------------------+

SELECT tumble(TIMESTAMP '2001-02-16 20:38:40', interval '5' minute) FROM (VALUES(1));
+------------------------+
|         EXPR$0         |
+------------------------+
|2001-02-1620:35:00.0|
+------------------------+

Data type conversion functions

CAST

The CAST function converts the evaluated values of an expression from one data type to another data type.

• Syntax

  CAST (<expression> AS <data type>)

• expression

  Specifies one or more values whose data types you want to convert. An expression is a combination of operators and SQL functions that you can evaluate.

• data type

  Specifies the data type to which the specified values are converted. For example, you can specify INTEGER or DATE.

  The following statements provide examples on how to convert a string to a number, a number to a string, and a number of one numeric type to a number of another numeric type.

  SELECT CAST(456as VARCHAR(3)) FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  |456|
  +------------+
  1 row selected (0.08 seconds)
  
  SELECT CAST(456as CHAR(3)) FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  |456|
  +------------+
  1 row selected (0.093 seconds)

Functions to convert the data types of timestamps, dates, and times

TSQL supports the date and time formats that are shown in the following examples:

• 2008-12-15

• 22:55:55.123…

If your date and time use other formats, use the functions for data type conversion to perform the following operations:

• Convert values of the TIMESTAMP, DATE, TIME, INTEGER, FLOAT, or DOUBLE data type to strings of the VARCHAR data type.

• Convert strings to values of the DATE data type.

• Convert strings to values of the NUMBER data type.

The following table lists the functions for data type conversion that you can use in TSQL queries.

Format specifiers for date and time conversion

The following table lists the Joda-Time format specifiers that can be used for date and time conversion.

• TO_CHAR examples

  Convert a number, date, time, or timestamp expression to a string.

  SELECT TO_CHAR(1256.789383,'#,###.###') FROM (VALUES(1));
  +------------+
  |   EXPR$0   |
  +------------+
  |1,256.789|
  +------------+
  1 row selected (1.767 seconds)
  
  SELECT TO_CHAR(125677.4567,'#,###.###') FROM (VALUES(1));
  +--------------+
  |    EXPR$0    |
  +--------------+
  |125,677.457|
  +--------------+
  1 row selected (0.083 seconds)
  
  SELECT TO_CHAR((CAST('2008-2-23' AS DATE)),'yyyy-MMM-dd') FROM (VALUES(1));
  +--------------+
  |    EXPR$0    |
  +--------------+
  |2008-Feb-23|
  +--------------+
  1 row selected (0.166 seconds)
  
  SELECT TO_CHAR(CAST('12:20:30' AS TIME),'HH mm ss') FROM (VALUES(1));
  +------------+
  |   EXPR$0   |
  +------------+
  |122030|
  +------------+
  1 row selected (0.07 seconds)
  
  SELECT TO_CHAR(CAST('2015-2-23 12:00:00' AS TIMESTAMP),'yyyy MMM dd HH:mm:ss') FROM (VALUES(1));
  +-----------------------+
  |        EXPR$0         |
  +-----------------------+
  |2015Feb2312:00:00|
  +-----------------------+
  1 row selected (0.142 seconds)

• TO_DATE examples

  Convert a string to a date.

  SELECT TO_DATE('2015-FEB-23','yyyy-MMM-dd') FROM (VALUES(1));
  +------------+
  |   EXPR$0   |
  +------------+
  |2015-02-23|
  +------------+
  1 row selected (0.077 seconds)
  
  SELECT EXTRACT(year from mydate)`extracted year` FROM (SELECT TO_DATE('2015-FEB-23','yyyy-MMM-dd') AS mydate FROM (VALUES(1)));
  
  +------------+
  |   myyear   |
  +------------+
  |2015|
  +------------+
  1 row selected (0.128 seconds)

  Convert a UNIX timestamp to a date.

  SELECT TO_DATE(1427849046000) FROM (VALUES(1));
  
  +------------+
  |   EXPR$0   |
  +------------+
  |2015-04-01|
  +------------+
  1 row selected (0.082 seconds)

• TO_TIME examples

  Convert a string to a timestamp.

  SELECT to_time(82855000) FROM (VALUES(1));
  +------------+
  | EXPR$0     |
  +------------+
  | 23:00:55   |
  +------------+
  1 row selected (0.086 seconds)

• TO_TIMESTAMP examples

  Convert a date to a timestamp.

  ```sql
  SELECT TO_TIMESTAMP('2008-2-23 12:00:00', 'yyyy-MM-dd HH:mm:ss') FROM (VALUES(1));
  +------------------------+
  |         EXPR$0         |
  +------------------------+
  | 2008-02-23 12:00:00.0  |
  +------------------------+
  1 row selected (0.126 seconds)

  Convert a UNIX time value to a timestamp.

  SELECT TO_TIMESTAMP(1427936330) FROM (VALUES(1));
  +------------------------+
  |         EXPR$0         |
  +------------------------+
  | 2015-04-01 17:58:50.0  |
  +------------------------+
  1 row selected (0.114 seconds)

  Convert a UTC date to a timestamp that includes a time zone offset in the value.

  SELECT TO_TIMESTAMP('2015-03-30 20:49:59.0 UTC', 'YYYY-MM-dd HH:mm:ss.s z') AS Original, 
         TO_CHAR(TO_TIMESTAMP('2015-03-30 20:49:59.0 UTC', 'YYYY-MM-dd HH:mm:ss.s z'), 'z') AS New_TZ 
  FROM (VALUES(1));
  +------------------------+---------+
  |        Original        | New_TZ  |
  +------------------------+---------+
  | 2015-03-30 20:49:00.0  | UTC     |
  +------------------------+---------+
  1 row selected (0.148 seconds)