---
title: "SPI_fnumber"
id: spi-spi-fnumber
pg_version: "20devel"
---

<a id="spi-spi-fnumber"></a>

# SPI_fnumber — determine the column number for the specified column name

## Synopsis

```
int SPI_fnumber(TupleDesc rowdesc, const char * colname)
```

<a id="id-1.8.12.9.5.5"></a>

## Description

`SPI_fnumber` returns the column number for the column with the specified name. 

If `colname` refers to a system column (e.g., `ctid`) then the appropriate negative column number will be returned. The caller should be careful to test the return value for exact equality to `SPI_ERROR_NOATTRIBUTE` to detect an error; testing the result for less than or equal to 0 is not correct unless system columns should be rejected. 

<a id="id-1.8.12.9.5.6"></a>

## Arguments

**`TupleDesc rowdesc`**

 input row description **`const char * colname`**

 column name <a id="id-1.8.12.9.5.7"></a>

## Return Value

Column number (count starts at 1 for user-defined columns), or `SPI_ERROR_NOATTRIBUTE` if the named column was not found.