nullIf

nullIf(X, Y)

X/Y can be a scalar or vector, or an expression that returns a scalar or vector.

• For two scalars, the function returns a NULL value if the values and data types of X and Y are equal. Otherwise, returns X.

• For two vectors of equal length, the function conducts the aforementioned calculation with each pair of elements in X and Y at the same position.

• For a scalar and a vector, the function conducts the aforementioned calculation on the scalar and each element of the vector.

t = table(`APPL`IBM`AMZN`IBM`APPL`AMZN as sym, 10.1 11.2 11.3 12 10.6 10.8 as val)
select nullIf(sym, `AMZN) from t

select * from t where nullIf(sym, `AMZN)!=NULL