mariadb-information-functions

name

mariadb-information-functions

description

MariaDB information functions — session and server metadata: LAST_INSERT_ID, ROW_COUNT, FOUND_ROWS, DATABASE/SCHEMA, USER/CURRENT_USER/SESSION_USER/SYSTEM_USER, CURRENT_ROLE, VERSION, CONNECTION_ID, CHARSET, COLLATION, COERCIBILITY, BENCHMARK, DEFAULT, LAST_VALUE, ROWNUM, BINLOG_GTID_POS, DECODE_HISTOGRAM. Use when writing SQL that reads auto-increment IDs, affected/found row counts, the current database or authenticated user, the server version, or connection/session metadata in MariaDB.

MariaDB Information Functions

Last updated: 2026-07-20

Catalog of every built-in information function in MariaDB, with signature and a one-line semantic summary per entry. For a function not listed here, fall back to the canonical reference at https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/information-functions.

Default context: Assume MariaDB 11.8 LTS unless the user specifies another version. Functions with a *(since X.Y)* annotation are only available from that version onward; everything else is in every current LTS branch (10.6, 10.11, 11.4, 11.8).

What LLMs Often Miss

If the agent writes / assumes…	…prefer the MariaDB form
LAST_INSERT_ID() after a multi-row INSERT and expects the ID of the last row inserted	It returns the first automatically-generated AUTO_INCREMENT value of that statement, not the last. Subsequent rows' IDs are implied by increment, not returned
Worrying that LAST_INSERT_ID() is contaminated by other sessions inserting concurrently	It's per-connection (server-side, tied to the session), not global — safe under concurrency. Read it immediately after the INSERT on the same connection; a stored function or trigger that changes it restores the prior value on exit, so callers outside it never see the trigger's value
ROW_COUNT() returning 0 after a SELECT	It returns -1 for any statement that returns a result set (SELECT, SHOW, DESC, HELP), even an empty one, and after a failed/rolled-back statement. 0 means a DDL or no-result statement genuinely affected nothing
Assuming ROW_COUNT() after UPDATE always means "rows actually changed"	It's the number of rows changed by default, but becomes the number of rows matched by the WHERE clause when the client connects with CLIENT_FOUND_ROWS — the two can differ
Reaching for SQL_CALC_FOUND_ROWS + FOUND_ROWS() to get a total count alongside a LIMITed page of results	Legacy pattern, discouraged for new code — it disables some query optimizations. Prefer a separate SELECT COUNT(*) ... with the same WHERE clause (see mariadb-select)
DATABASE() returning an empty string '' when no database is selected	It returns NULL, not '' — test with IS NULL
Parsing VERSION() as a bare version number	The string embeds a -MariaDB suffix (e.g. 11.8.1-MariaDB) plus optional -log/-debug/-embedded/-valgrind suffixes — always account for it when detecting the fork or parsing the numeric part
Treating USER() and CURRENT_USER() as interchangeable	USER() is the user/host the client presented at connection; CURRENT_USER() is the account actually used to check privileges (e.g. the DEFINER inside a stored routine with SQL SECURITY DEFINER). They differ whenever a role, proxy user, or DEFINER context is involved — a real security-relevant distinction
Assuming SESSION_USER() is just another alias for USER()	That was true only before 11.7. From 11.7 onward SESSION_USER() instead captures CURRENT_USER() as of session start and stays fixed inside stored routines/views (unlike CURRENT_USER(), which can change under DEFINER). SYSTEM_USER() remains a plain synonym for USER() in both eras — don't conflate the two *_USER() synonyms

Functions

BENCHMARK

BENCHMARK(count,expr)
The BENCHMARK() function executes the expression expr repeatedly count times.

BINLOG_GTID_POS

BINLOG_GTID_POS(binlog_filename,binlog_offset)
The BINLOG_GTID_POS() function takes as input an old-style binary log position in the form of a file name and a file offset.

CHARSET

CHARSET(str)
Returns the character set of the string argument.

COERCIBILITY

COERCIBILITY(str)
Returns the collation coercibility value of the string argument.

COLLATION

COLLATION(str)
Returns the collation of the string argument.

CONNECTION_ID

CONNECTION_ID()
Returns the connection ID for the connection.

CURRENT_ROLE

CURRENT_ROLE, CURRENT_ROLE()
Returns the current role name.

CURRENT_USER

CURRENT_USER, CURRENT_USER()
Returns the user name and host name combination for the MariaDB account that the server used to authenticate the current client.

DATABASE

DATABASE()
Returns the default (current) database name as a string in the utf8 character set.

DECODE_HISTOGRAM

DECODE_HISTOGRAM(hist_type,histogram)
Returns a string of comma separated numeric values corresponding to a probability distribution represented by the histogram of type hist_type (SINGLE_PREC_HB or DOUBLE_PREC_HB).

DEFAULT

DEFAULT(col_name)
Returns the default value for a table column.

FOUND_ROWS

FOUND_ROWS()
A SELECT statement may include a LIMIT clause to restrict the number of rows the server returns to the client.

LAST_INSERT_ID

LAST_INSERT_ID(), LAST_INSERT_ID(expr)
LAST_INSERT_ID() (no arguments) returns the first automatically generated value successfully inserted for an AUTO_INCREMENT column as a result of the most recently executed INSERT\ statement.

LAST_VALUE

LAST_VALUE(expr,[expr,...])
LAST_VALUE() evaluates all expressions and returns the last.

ROWNUM

ROWNUM()
ROWNUM() returns the current number of accepted rows in the current context.

ROW_COUNT

ROW_COUNT()
ROW_COUNT() returns the number of rows updated, inserted or deleted by the preceding statement.

SCHEMA

SCHEMA()
This function is a synonym for DATABASE().

SESSION_USER

SESSION_USER()
{% tabs %} {% tab title="Current" %} Shows the value of CURRENT_USER() when the session was created, that is, it shows a user@host pair from the mysql.global_priv table, like CURRENT_USER(), but unlike CURRENT_USER() it will not change inside stored routines and views.

SYSTEM_USER

SYSTEM_USER()
SYSTEM_USER() is a synonym for USER().

USER

USER()
Returns the current MariaDB user name and host name, given when authenticating to MariaDB, as a string in the utf8 character set.

VERSION

VERSION()
Returns a string that indicates the MariaDB server version.

See Also

• mariadb-select — why SQL_CALC_FOUND_ROWS/FOUND_ROWS() is discouraged in favor of a separate COUNT(*) query
• mariadb-create-table — AUTO_INCREMENT columns (source of LAST_INSERT_ID()) and column DEFAULT clauses (source of DEFAULT(col))
• mariadb-window-functions — LAST_VALUE(expr) OVER (...) as a window function, distinct from its non-window scalar form
• Canonical reference on mariadb.com/docs: https://mariadb.com/docs/server/reference/sql-functions/secondary-functions/information-functions