Skip to content

Move 'Data Types across Database Platforms' section to Reference #396

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
jd-foster merged 1 commit into from
Apr 30, 2026
Merged

Move 'Data Types across Database Platforms' section to Reference #396

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
48 changes: 48 additions & 0 deletions learners/reference.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -177,3 +177,51 @@ covered in this lesson.
</table>


## Data Types across Database Platforms

Different database systems use different names for data types. Please refer to the documentation of your specific database software.

| Data type | Description |
| ----------------------------------------------------- | :------------------------------------------------------------------------------------------------------- |
| CHARACTER(n) or CHAR(n) | Character string. Fixed-length n |
| VARCHAR(n) or CHARACTER VARYING(n) | Character string. Variable length. Maximum length n |
| BINARY(n) | Binary string. Fixed-length n |
| BOOLEAN | Stores TRUE or FALSE values |
| VARBINARY(n) or BINARY VARYING(n) | Binary string. Variable length. Maximum length n |
| INTEGER | Integer numerical (no decimal) |
| SMALLINT | Integer numerical (no decimal) |
| INTEGER | Integer numerical (no decimal) |
| BIGINT | Integer numerical (no decimal) |
| NUMERIC(p,s) or DECIMAL(p,s) or NUMBER(p,s) | Exact numerical, precision p (significant digits), scale s (digits in the fraction part). |
| FLOAT(p) | Approximate numerical (a floating point number) with p mantissa precision bits |
| REAL | Approximate numerical, same as FLOAT(p) but p will depend on the database system |
| FLOAT | Approximate numerical, using the default value of p for the database system |
| DOUBLE PRECISION | Approximate numerical |
| DATE | Stores year, month, and day values |
| TIME | Stores hour, minute, and second values |
| DATETIME or TIMESTAMP | Stores year, month, day, hour, minute, and second values |
| INTERVAL | Composed of a number of integer fields, representing a period of time, depending on the type of interval |
| ARRAY | A set-length and ordered collection of elements |
| MULTISET | A variable-length and unordered collection of elements |
| XML | Stores XML data |

The following table shows some of the common names of data types used with various database platforms:

| Data type | SQLite | Access (not SQL) | SQLServer | Oracle | MySQL | PostgreSQL |
| :-------------------| :-------| :----------------------------- | :---------------------------- | :--------------- | :------------ | :-------------|
| boolean | INTEGER | Yes/No | BIT | INTEGER | INTEGER | BOOLEAN |
| integer | INTEGER | Number (Integer) | INT | NUMBER | INT / INTEGER | INTEGER |
| float | REAL | Number (Single / Double) | FLOAT / REAL | NUMBER | FLOAT | NUMERIC /REAL |
| currency | REAL | Currency | MONEY | N/A | N/A | MONEY |
| string (fixed) | TEXT | N/A | CHAR | CHAR | CHAR | CHAR |
| string (variable) | TEXT | Short (\<255 char) / Long Text | VARCHAR | VARCHAR2 | VARCHAR | VARCHAR |
| binary data | BLOB | Attachment | BINARY / IMAGE (\<2GB) | RAW / BLOB | BLOB / BINARY | BYTEA |

Binary data is data with no specfic type (BLOB stands for _Binary Large OBject_) and is typically stored in the database exactly as given by the user.

Further information can be found at these references:
- [SQLite](https://sqlite.org/datatype3.html)
- [SQLServer](https://learn.microsoft.com/en-us/sql/t-sql/data-types/data-types-transact-sql)
- [Oracle](https://docs.oracle.com/en/database/oracle/oracle-database/19/sqlqr/Data-Types.html)
- [MySQL](https://dev.mysql.com/doc/refman/9.6/en/data-types.html)
- [PostgreSQL](https://www.postgresql.org/docs/current/datatype.html)
50 changes: 0 additions & 50 deletions learners/sql-cheat-sheet.md
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -41,56 +41,6 @@ Sort results using `ASC` for ascending order or `DESC` for descending order:

SELECT * FROM table_name ORDER BY column_name_1 ASC, column_name_2 DESC;

Data Types across Database Platforms
------------------------------------

Different database systems use different names for data types. Please refer to the documentation of your specific database software.

| Data type | Description |
| ----------------------------------------------------- | :------------------------------------------------------------------------------------------------------- |
| CHARACTER(n) or CHAR(n) | Character string. Fixed-length n |
| VARCHAR(n) or CHARACTER VARYING(n) | Character string. Variable length. Maximum length n |
| BINARY(n) | Binary string. Fixed-length n |
| BOOLEAN | Stores TRUE or FALSE values |
| VARBINARY(n) or BINARY VARYING(n) | Binary string. Variable length. Maximum length n |
| INTEGER | Integer numerical (no decimal) |
| SMALLINT | Integer numerical (no decimal) |
| INTEGER | Integer numerical (no decimal) |
| BIGINT | Integer numerical (no decimal) |
| NUMERIC(p,s) or DECIMAL(p,s) or NUMBER(p,s) | Exact numerical, precision p (significant digits), scale s (digits in the fraction part). |
| FLOAT(p) | Approximate numerical (a floating point number) with p mantissa precision bits |
| REAL | Approximate numerical, same as FLOAT(p) but p will depend on the database system |
| FLOAT | Approximate numerical, using the default value of p for the database system |
| DOUBLE PRECISION | Approximate numerical |
| DATE | Stores year, month, and day values |
| TIME | Stores hour, minute, and second values |
| DATETIME or TIMESTAMP | Stores year, month, day, hour, minute, and second values |
| INTERVAL | Composed of a number of integer fields, representing a period of time, depending on the type of interval |
| ARRAY | A set-length and ordered collection of elements |
| MULTISET | A variable-length and unordered collection of elements |
| XML | Stores XML data |

The following table shows some of the common names of data types used with various database platforms:

| Data type | SQLite | Access (not SQL) | SQLServer | Oracle | MySQL | PostgreSQL |
| :-------------------| :-------| :----------------------------- | :---------------------------- | :--------------- | :------------ | :-------------|
| boolean | INTEGER | Yes/No | BIT | INTEGER | INTEGER | BOOLEAN |
| integer | INTEGER | Number (Integer) | INT | NUMBER | INT / INTEGER | INTEGER |
| float | REAL | Number (Single / Double) | FLOAT / REAL | NUMBER | FLOAT | NUMERIC /REAL |
| currency | REAL | Currency | MONEY | N/A | N/A | MONEY |
| string (fixed) | TEXT | N/A | CHAR | CHAR | CHAR | CHAR |
| string (variable) | TEXT | Short (\<255 char) / Long Text | VARCHAR | VARCHAR2 | VARCHAR | VARCHAR |
| binary data | BLOB | Attachment | BINARY / IMAGE (\<2GB) | RAW / BLOB | BLOB / BINARY | BYTEA |

Binary data is data with no specfic type (BLOB stands for _Binary Large OBject_) and is typically stored in the database exactly as given by the user.

Further information can be found at these references:
- [SQLite](https://sqlite.org/datatype3.html)
- [SQLServer](https://learn.microsoft.com/en-us/sql/t-sql/data-types/data-types-transact-sql)
- [Oracle](https://docs.oracle.com/en/database/oracle/oracle-database/19/sqlqr/Data-Types.html)
- [MySQL](https://dev.mysql.com/doc/refman/9.6/en/data-types.html)
- [PostgreSQL](https://www.postgresql.org/docs/current/datatype.html)


Missing Data
------------
Expand Down