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You run EXPLAIN SELECT name FROM employees WHERE age > 30; but get an error. What is the most likely cause?

medium📝 Debug Q14 of 15
SQL - Indexes and Query Performance
You run EXPLAIN SELECT name FROM employees WHERE age > 30; but get an error. What is the most likely cause?
AThe EXPLAIN keyword is not supported in your SQL dialect
BThe query is missing a semicolon at the end
CThe table employees does not exist
DThe WHERE clause uses an invalid operator
Step-by-Step Solution
Solution:

  1. Step 1: Check common EXPLAIN errors

    EXPLAIN syntax is usually supported; missing semicolon rarely causes errors in many tools.

  2. Step 2: Consider table existence

    If the table does not exist, EXPLAIN cannot analyze the query and will error.

  3. Final Answer:

    The table employees does not exist -> Option C

  4. Quick Check:

    Missing table = EXPLAIN error [OK]
Quick Trick: Check if tables exist before EXPLAIN [OK]
Common Mistakes:
  • Assuming EXPLAIN is unsupported
  • Blaming missing semicolon
  • Thinking WHERE operator is invalid

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