| 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(*) querymariadb-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
