FYI Center for Database Administrator

INET_NTOA() - IP Address Number to String

2026-04-13T03:50:28+02:00

How to convert an IP address from number format to string using the INET_NTOA() function? INET_NTOA(int) is a MySQL built-in function that converts an IP address from number format to string. It uses the following conversion formula: INET_NTOA(int) = 'p 1 .p 2 .p 3 .p 4 ' where: p 1 = (int>&a... - Rank: 1467; Updated: 2026-04-13 03:50:00 -> Source

INET6_ATON() - IPv6 Address String to Number

2026-04-13T03:50:29+02:00

How to convert an IPv6 address from string format to number using the INET6_ATON() function? INET6_ATON(ip) is a MySQL built-in function that converts an IPv6 address from string format to number. But an IPv6 number is too big to be represented in decimal digits. So it is stored as a byte sequence, ... - Rank: 1312; Updated: 2026-04-13 03:50:00 -> Source

IS_IPV4_MAPPED() - IPv4-Mapped IPv6 Address

2026-04-13T03:50:33+02:00

How to detect an IPv6 Address that is IPv4 compatible using the IS_IPV4_MAPPED() function? IS_IPV4_MAPPED(ip) is a MySQL built-in function that returns 1 if the given IPv6 address is IPv4-mapped, 0 otherwise. The IPv6 address must be given in number format. An IPv4-mapped IPv6 address has 10 leading... - Rank: 1122; Updated: 2026-04-13 03:50:00 -> Source

MySQL Functions for Miscellaneous Purposes

2026-03-22T13:49:36+01:00

Where to find reference information and tutorials on MySQL database functions for Miscellaneous Purposes? I want to know how to use CAST(), SLEEP() and other miscellaneous functions. Here is a collection of reference information and tutorials on MySQL database functions for Miscellaneous Purposes co... - Rank: 2190; Updated: 2026-03-22 13:49:19 -> Source

COALESCE() - Finding First Non-NULL Value

2026-03-22T13:49:38+01:00

How to find the first non-NULL value from a list using the COALESCE() function? COALESCE(val1, val2, ...) is a MySQL built-in function that returns the first non-NULL value from a given list of values. For example: SELECT COALESCE(NULL, 'FYI', NULL, 3.14); -- +----------------------------- ------+--... - Rank: 1268; Updated: 2026-03-22 13:49:19 -> Source

CAST() - Casting Expression to Value

2026-03-22T13:49:37+01:00

How to cast an expression to a value of the given data type using the CAST() function? CAST(exp AS type) is a MySQL built-in function that casts an expression to a value of the given data type. For example: SET @exp = '-1.99 USD'; SELECT @exp, CAST(@exp AS SIGNED INTEGER), CAST(@exp AS UNSIGNED INTE... - Rank: 1155; Updated: 2026-03-22 13:49:19 -> Source

Differences of DECIMAL and FLOAT in SQL Server

2026-02-12T06:50:10+01:00

What Are the Differences between DECIMAL and FLOAT in SQL Server Transact-SQL? DECIMAL and FLOAT are both used to store numerical values. But they have the following main differences: DECIMAL(p,s) stores values with the decimal point fixed at the position of s (scale) digits from the right. The tota... - Rank: 3191; Updated: 2026-02-12 06:49:54 -> Source

IS_IPV4() - Detecting IPv4 Address

2026-02-02T04:57:20+01:00

How to detect an IPv4 Address using the IS_IPV4() function? IS_IPV4(ip) is a MySQL built-in function that returns 1 if the given value is a valid IPv4 address, 0 otherwise. For example: SELECT IS_IPV4('10.0.5.9'), IS_IPV4('10.0.5.256'); -- +---------------------+------- ----------------+-- | IS_IPV4... - Rank: 2586; Updated: 2026-02-02 04:56:49 -> Source

IS_IPV4_COMPAT() - IPv4-Compatible IPv6 Address

2026-02-02T04:57:21+01:00

How to detect an IPv6 Address that is IPv4 compatible using the IS_IPV4_COMPAT() function? IS_IPV4_COMPAT(ip) is a MySQL built-in function that returns 1 if the given IPv6 address is IPv4-compatible, 0 otherwise. The IPv6 address must be given in number format. An IPv4-compatible IPv6 address has 12... - Rank: 1922; Updated: 2026-02-02 04:56:49 -> Source

INET6_NTOA() - IPv6 Address Number to String

2026-02-02T04:57:19+01:00

How to convert an IPv6 address from number format to string using the INET6_NTOA() function? INET6_NTOA(int) is a MySQL built-in function that converts an IPv6 address from number format to string. For example: SET @ipv6 = UNHEX('FDFE0000000000005A55CAF FFEFA9089');SELECT HEX(@ipv6), INET6_NTOA(@ipv... - Rank: 1529; Updated: 2026-02-02 04:56:49 -> Source

IS_IPV6() - Detecting IPv6 Address

2026-01-24T02:45:24+01:00

How to detect an IPv4 Address using the IS_IPV6() function? IS_IPV6(ip) is a MySQL built-in function that returns 1 if the given value is a valid IPv6 address, 0 otherwise. For example: SELECT IS_IPV4('10.0.5.9'), IS_IPV4('10.0.5.256'); -- +---------------------+------- ----------------+-- | IS_IPV4... - Rank: 1869; Updated: 2026-01-24 02:44:50 -> Source

UPDATEXML() - Updating Child Element in XML

2026-01-24T02:45:28+01:00

How to update a child element in an XML document at a given location using the UPDATEXML() function? UPDATEXML(xml, path, subxml) is a MySQL built-in function that updates a child element in an XML document at a given location. For example: SET @xml = ' X Y '; SELECT UPDATEXML(@xml, '/a', ' Z '); +-... - Rank: 1846; Updated: 2026-01-24 02:44:50 -> Source

CHARSET() - Detecting Character Set Name

2025-10-24T14:58:23+02:00

How to detect the character set name associated to a given character string using the CHARSET() function? CHARSET(str) is a MySQL built-in function that returns the character set name associated to a given character string. A character set name refers to a set of rules to encode a set of characters ... - Rank: 2364; Updated: 2025-10-24 14:57:43 -> Source

VALUES() - Column Value for "ON DUPLICATE KEY UPDATE"

2025-10-24T14:58:22+02:00

How to obtain the inserting value of given column in the "ON DUPLICATE KEY UPDATE" clause using the VALUES() function? VALUES(col) is a MySQL built-in function that returns the inserting value of a given column and use it in the "ON DUPLICATE KEY UPDATE" clause. For example: CREATE TABLE MyTable (id... - Rank: 1416; Updated: 2025-10-24 14:57:43 -> Source

COERCIBILITY() - Character Collation Coercibility

2025-10-14T10:52:13+02:00

How to detect the collation coercibility associated to a given character string using the COERCIBILITY() function? COERCIBILITY(str) is a MySQL built-in function that returns the collation coercibility associated to a given character string. A collation coercibility refers to the coercibility index,... - Rank: 3950; Updated: 2025-10-14 10:51:32 -> Source

COLLATION() - Detecting Character Collation Name

2025-10-14T10:52:14+02:00

How to detect the character collation name associated to a given character string using the COLLATION() function? COLLATION(str) is a MySQL built-in function that returns the character collation name associated to a given character string. A character collation name refers to a set of rules to sort ... - Rank: 1695; Updated: 2025-10-14 10:51:32 -> Source

What Is Transport Network Substrate in Oracle

2025-09-30T09:35:08+02:00

What Is Transport Network Substrate (TNS) in Oracle? TNS, Transport Network Substrate, is a foundation technology, built into the Oracle Net foundation layer that works with any standard network transport protocol. ⇒ What Is ODBC in Oracle ⇐ What Is SQL*Plus in Oracle ⇑ Oracle Database Basic Conc... - Rank: 4990; Updated: 2025-09-30 09:34:10 -> Source

FORMAT_BYTES() - Formatting Bytes in Readable Units

2025-09-24T06:55:14+02:00

How to format a number of bytes in a human-readable unit using the FORMAT_BYTES() function? FORMAT_BYTES(con) is a MySQL built-in function that converts a number of bytes in a human-readable unit of KiB, MiG, GiB, TiB, PiB or EiB. For example: SELECT FORMAT_BYTES(9), FORMAT_BYTES(9*1024), FORMAT_BYT... - Rank: 4476; Updated: 2025-09-24 06:54:31 -> Source

FORMAT_PICO_TIME() - Formatting Picoseconds in Readable Units

2025-09-24T06:55:15+02:00

How to format a number of picoseconds in a human-readable unit using the FORMAT_PICO_TIME() function? FORMAT_PICO_TIME(con) is a MySQL built-in function that converts a number of picoseconds in a human-readable unit of ps, ns, ms, s, min, h, or d. For example: SELECT FORMAT_PICO_TIME(9), FORMAT_PICO... - Rank: 1533; Updated: 2025-09-24 06:54:31 -> Source

Oracle Database Basic Concepts

2025-09-18T16:21:53+02:00

Where to find answers to frequently asked questions I am new to Oracle database. Here is a list of frequently asked questions and their answers compiled by FYIcenter.com DBA team about Oracle database basic concepts: What Is Oracle in Oracle What Is an Oracle Database in Oracle What Is an Oracle Ins... - Rank: 6515; Updated: 2025-09-18 16:21:16 -> Source

DATABASE() - Name of Current Database

2025-06-18T11:07:24+02:00

How to obtain the name of the current database using the DATABASE() function? DATABASE() is a MySQL built-in function that returns the name of the current database. For example: USE mysql; Database changed SELECT DATABASE(); -- +------------+ -- | DATABASE() | -- +------------+ -- | mysql | -- +----... - Rank: 2631; Updated: 2025-06-18 11:06:33 -> Source

CURRENT_USER() - Authentication Name of Current User

2025-06-18T11:07:23+02:00

How to obtain the authentication name of the current user using the CURRENT_USER() function? CURRENT_USER() is a MySQL built-in function that returns the authentication name of the current user. The authentication name is a combination of "User" and "Host" columns in the mysql.user table and used to... - Rank: 2512; Updated: 2025-06-18 11:06:33 -> Source

FOUND_ROWS() - Row Count from Last SELECT Statement

2025-04-11T14:43:11+02:00

How to obtain the number of rows found by the last SELECT statement using the FOUND_ROWS() function? FOUND_ROWS() is a MySQL built-in function that returns the number of rows found by the last SELECT statement. For example: SELECT help_topic_id, name FROM mysql.help_topic; -- +---------------+------... - Rank: 7448; Updated: 2025-04-11 14:42:19 -> Source

ICU_VERSION() - ICU (International Components for Unicode) Version

2025-04-11T14:43:12+02:00

How to obtain the version number of the ICU (International Components for Unicode) library using the ICU_VERSION() function? ICU_VERSION() is a MySQL built-in function that returns the version number of the ICU (International Components for Unicode) library. For example: SELECT ICU_VERSION(); -- +--... - Rank: 3778; Updated: 2025-04-11 14:42:19 -> Source