op:col() as
Identifies a column where the column name is unique and a qualifier on the column name isn't necessary (and might not exist).
In positions where only a column name can appear, the unqualified column name can also be provided as a string. Qualified column names cannot be provided as a string.
The returned value from this function can be modified by any of the functions described in Expression Functions For Processing Column Values in the Application Developer's Guide
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