---
title: "MySQL to Oracle data types"
description: "Every MySQL data type that Oracle stores differently, what the converter writes for it, when, and the report line."
canonical: https://intosql.com/docs/types/mysql-to-oracle
last_updated: 2026-10-15
---

# MySQL to Oracle data types

Each row is a type from MySQL that Oracle stores differently: what the Oracle script gets, why, and the line the report writes about it. The rows come from the converter's own rules, so this page matches what it does.

**Convert in the browser:** [MySQL to Oracle](/mysql-to-oracle) opens the converter set up for this pair. The [MySQL to Oracle migration guide](/docs/migrations/mysql-to-oracle) covers dumping, loading and the rules for keys, indexes and names.

A report line is a fix when the converter changed something and lists it, or a problem when a value or object is worth a look.

## Numbers

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| UNSIGNED integers | NUMBER wide enough for the range, with a CHECK that it isn't negative | Oracle's NUMBER holds any integer of the widths MySQL has; the check keeps negative values out as MySQL did. | None |
| ZEROFILL and display widths | dropped | Zero padding is a way of showing a number, not part of it. The numbers are kept; format them when you read them if the padding matters. | `zerofill_dropped` (fix) |
| FLOAT(M,D) | BINARY_FLOAT or BINARY_DOUBLE, without the scale | Oracle's binary floats have no fixed scale. The stored values are copied as they are. | `float_scale_dropped` (fix) |
| DECIMAL(p,s) | NUMBER(p,s) up to 38 digits; VARCHAR2 beyond | Oracle's NUMBER holds 38 digits. Wider decimals are kept as text so every digit stays exact. | `decimal_as_text` (fix) |

## Booleans and bits

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| TINYINT(1), BOOL | NUMBER(1) with a CHECK of 0 and 1 when every value is 0 or 1, else NUMBER(3) | MySQL's BOOL is a TINYINT(1) that can hold any number from -128 to 127. Oracle before 23ai has no boolean column, so a column of 0 and 1 is NUMBER(1) with a check; one that holds 2 or -1 keeps its numbers. | `bool_kept_numeric` (fix) |
| BIT(1), BIT(n) | NUMBER(1), NUMBER(19) up to 63 bits, NUMBER(20) for BIT(64) | Bit fields are stored as the number their bits make. | None |

## Text

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| empty strings and empty binary values | NULL | Oracle stores an empty string as NULL, so a value that was ' reads back as NULL. The report counts them per column. | `empty_string_null` (problem) |
| CHAR(n), VARCHAR(n) | VARCHAR2(n CHAR), counting characters | Lengths count characters as MySQL's do, and MySQL returns CHAR values without trailing spaces, as VARCHAR2 keeps them. | None |
| VARCHAR(n) and TEXT longer than 4000 bytes | CLOB | A VARCHAR2 holds 4000 bytes by default, so longer text is a CLOB; a column whose values all fit keeps VARCHAR2. | `text_as_lob` (fix) |
| NUL bytes in text | kept | VARCHAR2 and CLOB can hold a NUL character, so the value is copied as it is. | None |
| text that isn't valid in its character set | the bad bytes as the replacement character | Text has to be read as characters to be written as VARCHAR2. | `invalid_utf8_replaced` (problem) |

## Enums and sets

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| ENUM | VARCHAR2 with a CHECK of its values | Text with a check keeps the same values. | None |
| ENUM holding '' (MySQL's error value) | NULL | MySQL stores an empty string when an invalid value goes into an ENUM in a lenient SQL mode. Oracle stores it as NULL, which the check allows, and the report counts it with the other empty values. | None |
| ENUM holding values outside its list | no CHECK | Values the list doesn't name would fail the check, so the check isn't created. | `enum_check_skipped` (problem) |
| SET | VARCHAR2 as MySQL writes it ('a,b') | Oracle has no set type; the text is the one MySQL returns. | None |

## Dates and times

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| zero, partial or impossible dates (0000-00-00, 2024-02-30) | NULL | Oracle only stores real calendar dates. MySQL keeps zero and impossible dates when its SQL mode allows them; they become NULL and the report counts them. | `invalid_date_null` (problem) |
| DEFAULT '0000-00-00' | no default | A default Oracle can't store is left out rather than replaced with a made-up date. | `zero_date_default` (fix) |
| TIME | INTERVAL DAY TO SECOND, which holds durations | Oracle has no time-of-day type, and MySQL's TIME is a duration from -838:59:59 to 838:59:59; an interval holds every value. | None |
| YEAR | NUMBER(4) with a CHECK of its range | Oracle has no year type; the check keeps the same values MySQL allows. | None |
| DATETIME | TIMESTAMP | A DATETIME is a wall-clock reading without a time zone, like TIMESTAMP. DATE becomes Oracle's DATE, which also holds a time of day that stays at midnight. | None |
| TIMESTAMP | TIMESTAMP WITH TIME ZONE in the zone the dump states, UTC when it states none | A TIMESTAMP is a moment. Dumps state the zone they wrote it in (mysqldump writes UTC); without that, the values are read as UTC and the report says so. | `timestamp_zone_assumed` (problem) |

## Binary

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| BINARY, VARBINARY, BLOB | RAW up to 2000 bytes, else BLOB | Bytes stay bytes. | None |

## JSON, spatial and other types

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| JSON | CLOB | Oracle's JSON functions read JSON from text on every version, and a CLOB keeps values of any size. | None |
| GEOMETRY, POINT, POLYGON... | BLOB holding WKB | WKB is the standard form every spatial library reads; SDO_GEOMETRY needs Oracle Spatial's metadata. | `geometry_as_blob` (fix) |
| INET4, INET6, UUID (MariaDB) | VARCHAR2(39), VARCHAR2(36) | Oracle has neither type; the text is the one MariaDB returns. | None |
| geometries in a dump without CREATE TABLE | BLOB holding WKB | MySQL's geometry format is recognised from the values and stored as standard WKB. | `geometry_inferred` (fix) |
| types IntoSQL doesn't know | CLOB | Text holds any value; change the type after loading. | `unknown_type` (problem) |
| values that don't fit their column | NULL | A damaged or hand-written dump can hold values its column can't; they become NULL so the rest loads. | `invalid_value_null` (problem) |
| unreadable geometries | NULL | Bytes that aren't a geometry can't be stored as one. | `bad_geometry` (problem) |
| VECTOR(n) (MariaDB 11.7+) | CLOB with the floats as a JSON array | Only Oracle 23ai has a vector type; a JSON array keeps every float on every version. | `type_replaced` (fix) |

## Counters and identities

| In MySQL | In Oracle | Why | Report line |
| --- | --- | --- | --- |
| AUTO_INCREMENT | GENERATED BY DEFAULT ON NULL AS IDENTITY, restarted past the copied ids | The copied ids load as they are, and the counter continues after the highest one or the dump's AUTO_INCREMENT, whichever is higher. | None |
| MyISAM AUTO_INCREMENT on the second column of a key | one counter for the table | MyISAM counts per group of the key's first column; Oracle has one counter per table. | `myisam_group_autoincrement` (problem) |

## Other pairs

- MySQL into [PostgreSQL](/docs/types/mysql-to-postgresql), [MySQL](/docs/types/mysql-to-mysql), [MariaDB](/docs/types/mysql-to-mariadb), [SQLite](/docs/types/mysql-to-sqlite), [SQL Server](/docs/types/mysql-to-sql-server)
- Into Oracle from [MariaDB](/docs/types/mariadb-to-oracle), [PostgreSQL](/docs/types/postgresql-to-oracle), [SQL Server](/docs/types/sql-server-to-oracle), [SQLite](/docs/types/sqlite-to-oracle), [Oracle](/docs/types/oracle-to-oracle)
- [Every pair](/docs/types#from-one-database-to-another)