Which SQL statement correctly creates an index named idx_email on the email column of the customers table?

easy📝 Syntax Q3 of 15

SQL - Indexes and Query Performance

Which SQL statement correctly creates an index named idx_email on the email column of the customers table?

AALTER TABLE customers ADD INDEX idx_email(email);

BCREATE TABLE idx_email ON customers(email);

CCREATE INDEX idx_email ON customers(email);

DCREATE UNIQUE INDEX idx_email ON customers(email);

Step-by-Step Solution

Solution:

Step 1: Identify correct syntax
The standard SQL syntax to create an index is CREATE INDEX index_name ON table(column);
Step 2: Evaluate options
CREATE INDEX idx_email ON customers(email); matches the correct syntax. CREATE TABLE idx_email ON customers(email); is invalid syntax. ALTER TABLE customers ADD INDEX idx_email(email); is MySQL-specific but not standard and may not always be correct. CREATE UNIQUE INDEX idx_email ON customers(email); creates a unique index, which is different from a normal index.
Final Answer:
CREATE INDEX idx_email ON customers(email); -> Option C
Quick Check:
Standard index creation uses CREATE INDEX [OK]

Quick Trick: Use CREATE INDEX index_name ON table(column) [OK]

Common Mistakes:

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