Arroyo’s Scalar function implementations are based on Apache DataFusion and these docs are derived from the DataFusion function reference.

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coalesce

Returns the first of its arguments that is not null. Returns null if all arguments are null. This function is often used to substitute a default value for null values. 
coalesce(expression1[, ..., expression_n])
Arguments
  • expression1, expression_n: Expression to use if previous expressions are null. Can be a constant, column, or function, and any combination of arithmetic operators. Pass as many expression arguments as necessary.

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nullif

Returns null if expression1 equals expression2; otherwise it returns expression1. This can be used to perform the inverse operation of coalesce. 
nullif(expression1, expression2)
Arguments
  • expression1: Expression to compare and return if equal to expression2. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: Expression to compare to expression1. Can be a constant, column, or function, and any combination of arithmetic operators.

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nvl

Returns expression2 if expression1 is NULL; otherwise it returns expression1. 
nvl(expression1, expression2)
Arguments
  • expression1: return if expression1 not is NULL. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: return if expression1 is NULL. Can be a constant, column, or function, and any combination of arithmetic operators.

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nvl2

Returns expression2 if expression1 is not NULL; otherwise it returns expression3. 
nvl2(expression1, expression2, expression3)
Arguments
  • expression1: conditional expression. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression2: return if expression1 is not NULL. Can be a constant, column, or function, and any combination of arithmetic operators.
  • expression3: return if expression1 is NULL. Can be a constant, column, or function, and any combination of arithmetic operators.

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ifnull

Alias of nvl.