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SQL_MODE=ORACLE

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Technical Guide for Migrating from Oracle to MariaDB

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From MariaDB 10.3, MariaDB's SQL_MODE = ORACLE setting enables compatibility with Oracle Database SQL syntax and behavior in MariaDB. This feature is particularly useful for organizations looking to migrate applications from Oracle Database to MariaDB while preserving the behavior and syntax of Oracle SQL. By setting the sql_mode to ORACLE, developers can ensure that their existing SQL scripts, application logic, and database interactions are compatible with MariaDB's behavior, easing the migration process. This page provides detailed information on supported Oracle SQL syntax, behavior differences between Oracle and MariaDB, and tips for adapting applications and scripts to work smoothly under this mode.

SET SQL_MODE='ORACLE';

All traditional MariaDB SQL/PSM syntax should work as before, as long as it does not conflict with Oracle's PL/SQL syntax. All MariaDB functions should be supported in both normal and Oracle modes.

Prior to MariaDB 10.3, MariaDB does not support Oracle's PL/SQL language, and SET SQL_MODE=ORACLE is only an alias for the following sql_mode in those versions:

SET SQL_MODE='PIPES_AS_CONCAT, ANSI_QUOTES, IGNORE_SPACE, NO_KEY_OPTIONS,
NO_TABLE_OPTIONS, NO_FIELD_OPTIONS, NO_AUTO_CREATE_USER';

From MariaDB 10.3, SET SQL_MODE=ORACLE is same as:

SET SQL_MODE='PIPES_AS_CONCAT,ANSI_QUOTES,IGNORE_SPACE,ORACLE,NO_KEY_OPTIONS,
NO_TABLE_OPTIONS,NO_FIELD_OPTIONS,NO_AUTO_CREATE_USER,SIMULTANEOUS_ASSIGNMENT';

Supported Syntax in Oracle Mode

Stored Procedures and Stored Functions

Oracle mode makes the following changes to Stored Procedures and Stored Functions:

Oracle syntax
Description

CREATE PROCEDURE p1 (param OUT INT)

ANSI uses (OUT param INT)

CREATE PROCEDURE p1 (a IN OUT INT)

ANSI uses (INOUT param INT)

AS before function body

CREATE FUNCTION f1 RETURN NUMBER AS BEGIN...

IS before function body

CREATE FUNCTION f1 RETURN NUMBER IS BEGIN...

If function has no parameters then parentheses must be omitted

Example: CREATE PROCEDURE p1 AS BEGIN NULL; END;

CREATE PROCEDURE p1 AS BEGIN END p1;

Optional routine name after END keyword. MDEV-12089

CREATE FUNCTION f1(a VARCHAR)

VARCHAR can be used without length for routine parameters and RETURN clause. The length is inherited from the argument at call time. MDEV-10596

CREATE AGGREGATE FUNCTION f1( )

Creates an aggregate function, which performs the function against a set of rows and returns one aggregate result.

No CALL needed in Stored Procedures

In Oracle mode one can call other stored procedures with name only. MDEV-12107

RETURN. Can also be used in stored procedures

ANSI uses RETURNS. MariaDB mode only supports RETURNS in stored functions

Cursors

Oracle mode makes the following changes to Cursors:

Oracle syntax
Description

CREATE PROCEDURE p1 AS CURSOR cur IS (SELECT a, b FROM t1); BEGIN FOR rec IN cur ...

Explicit cursor with FOR loop. MDEV-10581

CREATE PROCEDURE p1 AS rec IN (SELECT a, b FROM t1)

Implicit cursor with FOR loop. MDEV-12098

CURSOR c(prm_a VARCHAR2, prm_b VARCHAR2) ... OPEN c(1,2)

Cursor with parameters. MDEV-10597

CURSOR c(prm_a VARCHAR2, prm_b VARCHAR2) ... FOR rec in c(1,2)

Cursor with parameters and FOR loop. MDEV-12314

s %ISOPEN, %ROWCOUNT, %FOUND, %NOTFOUND

Explicit cursor attributes. MDEV-10582

LOOP

Oracle mode makes the following changes to LOOP:

Oracle syntax
Description

FOR i IN 1..10 LOOP ... END LOOP

Numeric FOR loop. MDEV-10580

GOTO

GOTO statement. MDEV-10697

<<label>> used with GOTO

ANSI uses label:. MDEV-10697

To leave loop block: EXIT [ label ] [ WHEN bool_expr ]

ANSI syntax is IF bool_expr THEN LEAVE label

[<<label>>] WHILE boolean_expression LOOP statement... END LOOP [ label ] ;

Oracle style WHILE loop

CONTINUE [ label ] [ WHEN boolean_expression]

CONTINUE is only valid inside a loop

Variables

Oracle syntax
Version
Description

var:= 10; Can also be used with MariaDB systemvariables

10.3

MariaDB uses SET var= 10;

var INT := 10

10.3

Default variable value

var1 table_name.column_name%TYPE

10.3

Take data type from a table column. MDEV-10577

var2 var1%TYPE

10.3

Take data type from another variable

rec1 table_name%ROWTYPE

10.3

Take ROW structure from a table. MDEV-12133

rec2 rec1%ROWTYPE

10.3

Take ROW structure from ROW variable

CURSOR c1 IS SELECT a,b FROM t1; rec1 c1%ROWTYPE;

10.3

Take ROW structure from a cursor. MDEV-12011

Variables can be declared after cursor declarations

10.3

In MariaDB mode, variables must be declared before cursors. MDEV-10598

Triggers uses :NEW and :OLD

10.3

ANSI uses NEW and OLD. MDEV-10579

SQLCODE

10.3

Returns the number code of the most recent exception. Can only be used in Stored Procedures. MDEV-10578

SQLERRM

10.3

Returns the error message associdated to it's error number argument or SQLCODE if no argument is given. Can only be used in Stored Procedures. MDEV-10578

SQL%ROWCOUNT

10.3

Almost same as ROW_COUNT(). MDEV-10583

ROWNUM

10.6.1

Returns number of accepted rows

Exceptions

Oracle syntax
Description

BEGIN ... EXCEPTION WHEN OTHERS THEN BEGIN .. END; END;

Exception handlers are declared at the end of a block

TOO_MANY_ROWS, NO_DATA_FOUND, DUP_VAL_ON_INDEX

Predefined exceptions. MDEV-10839

RAISE TOO_MANY_ROWS ; .... EXCEPTION WHEN TOO_MANY_ROWS THEN ...

Exception can be used with RAISE and EXCEPTION...WHEN. MDEV-10840

CREATE OR REPLACE FUNCTION f1 (a INT) RETURN INT AS e1 EXCEPTION...

User defined exceptions. MDEV-10587

BEGIN Blocks

Oracle syntax
Description

BEGIN to start a block

MariaDB uses BEGIN NOT ATOMIC for anyonymous blocks. MDEV-10655

DECLARE is used before BEGIN

DECLARE a INT; b VARCHAR(10); BEGIN v:= 10; END;

WHEN DUP_VAL_ON_INDEX THEN NULL ; NULL; WHEN OTHERS THEN NULL

Do not require BEGIN..END in multi-statement exception handlers in THEN clause. MDEV-12088

Simple Syntax Compatibility

Oracle syntax
Version
Description

ELSIF

10.3

ANSI uses ELSEIF

SELECT UNIQUE

10.3

Same as SELECT DISTINCT. MDEV-12086

TRUNCATE TABLE t1 [DROP STORAGE] or [REUSE STORAGE]

10.3

DROP STORAGE and REUSE STORAGE are allowed as optional keywords for TRUNCATE TABLE. MDEV-10588

Subqueries in a FROM clause without an alias

10.6

SELECT * FROM (SELECT 1 FROM DUAL), (SELECT 2 FROM DUAL)

UNION, EXCEPT and INTERSECT all have the same precedence.

10.3

INTERSECT has higher precedence than UNION and EXCEPT in non-Oracle modes.

MINUS

10.6

MINUS is a synonym for EXCEPT.

Functions

Oracle syntax
Version
Description

ADD_MONTHS()

10.6.1

Added as a wrapper for DATE_ADD() to enhance Oracle compatibility. All modes.

CAST(expr as VARCHAR(N))

10.3

Cast expression to a VARCHAR(N). MDEV-11275

DECODE

10.3

In Oracle mode, compares and matches search expressions

LENGTH() is same as CHAR_LENGTH()

10.3

MariaDB translates LENGTH() to OCTET_LENGTH(). In all modes one can use LENGTHB() as a synonym to OCTET_LENGTH()

CHR(num)

10.3

Returns a VARCHAR(1) with character set and collation according to @@character_set_database and @@collation_database

substr('abc',0 ,3) same as substr('abc', 1 ,3)

10.3

Position 0 for substr() is same as position 1

SYS_GUID

10.6.1

Generates a globally unique identifier. Similar to UUID but without the -. All modes.

TO_CHAR

10.6.1

Added to enhance Oracle compatibility. All modes.

TRIM, LTRIM, RTRIM, LPAD and RPAD

10.3

Returns NULL instead of an empty string if returning an empty result. These functions can also be accessed outside of ORACLE mode by suffixing _ORACLE onto the end of the function name, such as TRIM_ORACLE.

Prepared Statements

Oracle mode makes the following changes to Prepared Statements:

Oracle syntax
Description

PREPARE stmt FROM 'SELECT :1, :2'

ANSI uses ?. MDEV-10801

EXECUTE IMMEDIATE 'INSERT INTO t1 SELECT (:x,:y) FROM DUAL' USING 10,20

Dynamic placeholders. MDEV-10801

Synonyms for Basic SQL Types

Oracle type
MariaDB synonym

VARCHAR2

VARCHAR

NUMBER(M[,D])

DECIMAL(M[,D])

NUMBER

DOUBLE

DATE (with time portion)

MariaDB DATETIME

RAW

VARBINARY

CLOB

LONGTEXT

BLOB

LONGBLOB

This was implemented as part of MDEV-10343.

If one does a SHOW CREATE TABLE in ORACLE mode on a table that has a native MariaDB DATE column, it will be displayed as mariadb_schema.date to not conflict with the Oracle DATE type.

Packages

The following syntax has been supported since MariaDB 10.3.5:

NULL Handling

Oracle mode makes the following changes to NULL handling:

NULL As a Statement

NULL can be used as a statement:

IF a=10 THEN NULL; ELSE NULL; END IF

Translating Empty String Literals to NULL

In Oracle, empty string ('') and NULL are the same thing,

By using sql_mode=EMPTY_STRING_IS_NULL you can get a similar experience in MariaDB:

SET sql_mode=EMPTY_STRING_IS_NULL;
SELECT '' IS NULL; -- returns TRUE
INSERT INTO t1 VALUES (''); -- inserts NULL

Concat Operator Ignores NULL

CONCAT() and || ignore NULL in Oracle mode. Can also be accessed outside of ORACLE mode by using CONCAT_OPERATOR_ORACLE. MDEV-11880 and MDEV-12143.

Reserved Words

There are a number of extra reserved words in Oracle mode.

SHOW CREATE TABLE

The SHOW CREATE TABLE statement will not display MariaDB-specific table options, such as AUTO_INCREMENT or CHARSET, when Oracle mode is set.

See Also

PreviousSQL_MODE=MSSQLNextFunction Differences Between MariaDB and MySQL

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