> For the complete documentation index, see [llms.txt](https://web.tipsytux.in/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://web.tipsytux.in/server-side/sql-injection/examples/union-based.md).

# Union Based

For a `UNION` query to work, two key requirements must be met: 

1. The individual queries must return the same number of columns. 
2. The data types in each column must be compatible with the individual queries.

***

## Steps

1. Determine the number of columns required in SQL injection to view the output.
   1. ' ORDER BY 1-- 
   2. ' ORDER BY 2-- 
   3. ' ORDER BY 3-- etc.
2. The aim here is we get an error when the number of columns is more than expected for the query.

***


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