When a multiple-column subquery is used in the WHERE clause of the outer query,the column names listed on the left side of the comparison operator must be enclosed in double-quotation marks.

Question

When a multiple-column subquery is used in the WHERE clause of the outer query,the column names listed on the left side of the comparison operator must be enclosed in double-quotation marks.​

Quizplus · Accepted Answer

The column names listed on the left side of the comparison operator in a multiple-column subquery do not need to be enclosed in double-quotation marks when used in the WHERE clause of the outer query. Single-quotation marks may be used for string comparisons. However, if the column name contains spaces or special characters, it should be enclosed in double-quotation marks or square brackets.

When a Multiple-Column Subquery Is Used in the WHERE Clause