[Solved] Why does this index creation fail? CREATE INDEX idx_fail ON sales(INCLUDE (region)); — Ans: No indexed columns specified before INCLUDE clause | PostgreSQL

PostgreSQL - Indexing Strategies

Why does this index creation fail? CREATE INDEX idx_fail ON sales(INCLUDE (region));

ANo indexed columns specified before INCLUDE clause

BINCLUDE clause cannot have multiple columns

CINCLUDE must be used only with UNIQUE indexes

Dregion column does not exist in sales table

Step-by-Step Solution

Solution:

Step 1: Understand index syntax requirements
INCLUDE clause must follow at least one indexed column; it cannot stand alone.
Step 2: Analyze the statement
The statement has INCLUDE but no indexed columns before it, causing failure.
Final Answer:
No indexed columns specified before INCLUDE clause -> Option A
Quick Check:
INCLUDE requires indexed columns first [OK]

Quick Trick: INCLUDE needs indexed columns before it [OK]

Common Mistakes:

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Why does this index creation fail? CREATE INDEX idx_fail ON sales(INCLUDE (region));