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A developer writes EXPLAIN PLAN FOR SELECT * FROM orders; but gets no output. What is the likely issue?

medium📝 Debug Q7 of 15
SQL - Indexes and Query Performance
A developer writes EXPLAIN PLAN FOR SELECT * FROM orders; but gets no output. What is the likely issue?
AThe orders table is empty
BThe query has a syntax error
CThe database requires a separate command to display the plan
DEXPLAIN PLAN FOR is not a valid syntax
Step-by-Step Solution
Solution:

  1. Step 1: Understand EXPLAIN PLAN FOR behavior

    Some databases store the plan and require a separate command to show it.

  2. Step 2: Identify why no output appears

    Without running the display command, no output is shown.

  3. Final Answer:

    The database requires a separate command to display the plan -> Option C

  4. Quick Check:

    EXPLAIN PLAN FOR needs display command [OK]
Quick Trick: Some DBs need extra step to show EXPLAIN PLAN [OK]
Common Mistakes:
  • Assuming syntax error without checking DB docs
  • Expecting immediate output from EXPLAIN PLAN FOR
  • Ignoring database-specific EXPLAIN behavior

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