Which two statements are true regarding the count function?

Question

Options

• AThe count function can be used only for CHAR, VARCHAR2, and NUMBER data types.
• BCount (*) returns the number of rows including duplicate rows and rows containing null value in any
• CCount (cust_id) returns the number of rows including rows with duplicate customer IDs and NULL
• DCount (distinct inv_amt) returns the number of rows excluding rows containing duplicates and NULL
• EA select statement using the COUNT function with a DISTINCT keyword cannot have a where clause.

• A
  5% (2)
• B
  79% (31)
• C
  13% (5)
• E
  3% (1)

Explanation

Using the COUNT Function The COUNT function has three formats: COUNT(DISTINCT expr) COUNT() returns the number of rows in a table that satisfy the criteria of the SELECT statement, including duplicate rows and rows containing null values in any of the columns. If a WHERE clause is included in the SELECT statement, COUNT() returns the number of rows that satisfy the condition in the WHERE clause. COUNT(expr) returns the number of non-null values that are in the column identified by expr. COUNT(DISTINCT expr) returns the number of unique, non-null values that are in the column identified by expr.

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