Evaluate the following query:
What would be the outcome of the above query?
A. It produces an error because flower braces have been used.
B. It produces an error because the data types are not matching.
C. It executes successfully and introduces an ‘s at the end of each PROMO_NAME in the output.
D. It executes successfully and displays the literal "{‘s start date was } * for each row in the output.
Correct Answer: C
Explanation/Reference:
Explanation:
So, how are words that contain single quotation marks dealt with? There are essentially two mechanisms available. The most popular of these is to add an additional single quotation mark next to each naturally occurring single quotation mark in the character string Oracle offers a neat way to deal with this type of character literal in the form of the alternative quote (q) operator. Notice that the problem is that Oracle chose the single quote characters as the special pair of symbols that enclose or wrap any other character literal. These character- enclosing symbols could have been anything other than single quotation marks. Bearing this in mind, consider the alternative quote (q) operator. The q operator enables you to choose from a set of possible pairs of wrapping symbols for character literals as alternatives to the single quote symbols. The options are any single-byte or multibyte character or the four brackets: (round brackets), {curly braces}, [squarebrackets], or <angle brackets>. Using the q operator, the character delimiter can effectively be changed from a single quotation mark to any other character
The syntax of the alternative quote operator is as follows:
q’delimiter’character literal which may include the single quotes delimiter’ where delimiter can be any character or bracket.
Alternative Quote (q) Operator
Specify your own quotation mark delimiter.
Select any delimiter.
Increase readability and usability.
SELECT department_name || q'[ Department’s Manager Id: ]’ || manager_id
AS "Department and Manager"
FROM departments;
Alternative Quote (q) Operator
Many SQL statements use character literals in expressions or conditions. If the literal itself contains a single quotation mark, you can use the quote (q) operator and select your own quotation mark delimiter.
You can choose any convenient delimiter, single-byte or multi byte, or any of the following character pairs: [ ], { }, ( ), or < >.
In the example shown, the string contains a single quotation mark, which is normally interpreted as a delimiter of a character string. By using the q operator, however, brackets [] are used as the quotation mark delimiters. The string between the brackets delimiters is interpreted as a literal character string.
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