====== ColumnExists(col_name) ======
Category:  Special function

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=====Description=====
This function tests whether a column named //col_name// exists in the input dataset.  TRUE is returned if the named column exists, otherwise, FALSE is returned.

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=====Arguments=====
^Argument^Type^Description^
|col_name|Text  |The name of a column to test for within the input dataset.  |

**Return value type:** Boolean (TRUE/FALSE)

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=====Remarks=====
This function is case sensitive.

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=====Examples=====
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**Sample dataset:**
^ Amount  ^ Description ^
|  200 | Product A  | 
|  3000| Product B  |

Given the dataset above, ColumnExists() would return the following results:
  columnexists('Description') = TRUE

  columnexists('description') = FALSE  //Function is case-sensitive

  columnexists('Price') = FALSE