Unsupported expressions found in spark sql unit test #2314

What is the problem the feature request solves?

Some unsupported expressions found in spark sql unit test:

• Abs: Duplicate of Add support for abs #1890
• Base64
• CheckOverflowInTableInsert
• Concat feat: support concat for strings #2604
• DayOfMonth | Month: Support more date part expressions #2315
• DenseRank
• Empty2Null
• ElementAt: because: Input is not an array, refer to datafusion map_extract
• FormatString
• Greatest: https://datafusion.apache.org/user-guide/sql/scalar_functions.html#greatest
• Literal: Comet cannot accelerate Literal because: Unsupported datatype ArrayType(LongType,true), refer to feat: Support Array Literal #2057
• NaNvl: refer to datafusion nanvl
• Pmod
• RowNumber
• Size
• StringSplit
• TimeAdd
• ToCharacter
• WidthBucket: Implementation in datafusion-spark feat(spark): implement Spark width_bucket function datafusion#17331

Describe the potential solution

No response

Additional context

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