Google Exam LookML-Developer Topic 2 Question 22 Discussion

A user reports the following SQL error when selecting the discounted sale price field:

ERROR: column ''order_items.sale_price''; must appear in the GROUP BY clause or be used in an aggregate function.

The developer checks the field definition and finds it to be:

measure: discounted_sale_price {

type: number

sql: ${sale_price} * 0.8 ;;

}

The developer also finds the LookML definition of the sale_price field to be:

dimension: sale_price {

type: number

sql: ${TABLE}.sale_price ;;

}

What is the likely cause of the SQL error?