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What is the purpose of the IFNULL() function in MySQL?
- A) To check if a value is null
- B) To return the first non-null value in a list of expressions
- C) To concatenate values from multiple rows into a single string
- D) To return the current date and time
Answer: B) To return the first non-null value in a list of expressions
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Which SQL command is used to create a primary key constraint in MySQL?
- A) ADD PRIMARY KEY
- B) CREATE PRIMARY KEY
- C) PRIMARY KEY
- D) SET PRIMARY KEY
Answer: A) ADD PRIMARY KEY
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What is the purpose of the BETWEEN operator in MySQL?
- A) To check if a value exists in a specified range
- B) To specify the starting row from which to retrieve rows in the result set
- C) To concatenate values from multiple rows into a single string
- D) To return the first non-null value in a list of expressions
Answer: A) To check if a value exists in a specified range
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Which SQL function is used to return the difference between two dates in MySQL?
- A) DATEDIFF()
- B) DATE_DIFF()
- C) DIFFERENCE()
- D) DATE_DIFFERENCE()
Answer: A) DATEDIFF()
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What is the purpose of the CONCAT() function in MySQL?
- A) To concatenate values from multiple rows into a single string
- B) To concatenate values with a specified separator
- C) To return the first non-null value in a list of expressions
- D) To return the current date and time
Answer: A) To concatenate values from multiple rows into a single string
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Which SQL command is used to create a unique constraint in MySQL?
- A) ADD UNIQUE
- B) CREATE UNIQUE
- C) UNIQUE
- D) SET UNIQUE
Answer: A) ADD UNIQUE
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What is the purpose of the SUM() function in MySQL?
- A) To calculate the average value of a numeric column
- B) To return the number of rows in a table
- C) To calculate the total value of a numeric column
- D) To concatenate values from multiple rows into a single string
Answer: C) To calculate the total value of a numeric column
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Which SQL function is used to return the current year in MySQL?
- A) YEAR()
- B) CURRENT_YEAR()
- C) GETYEAR()
- D) CURYEAR()
Answer: A) YEAR()
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What is the purpose of the MAX() function in MySQL?
- A) To return the maximum value of a column
- B) To return the minimum value of a column
- C) To return the average value of a column
- D) To return the total value of a column
Answer: A) To return the maximum value of a column
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Which SQL command is used to delete a unique constraint from a table in MySQL?
- A) DELETE UNIQUE
- B) REMOVE UNIQUE
- C) DROP UNIQUE
- D) ERASE UNIQUE
Answer: C) DROP UNIQUE
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