Solution:Step 1: Understand NULL from JSON path extractionIf the specified path does not exist in the JSON data, the operator returns NULL.Step 2: Check other optionsThe syntax is correct; #>> is valid for text extraction; invalid JSON would cause errors, not NULL.Final Answer:The path '{address,cit

[Solved] Consider the query:SELECT data #>> '{address,city}' FROM customers;If this query returns NULL unexpectedly, what is the most likely cause? | PostgreSQL

PostgreSQL - JSON and JSONB

Consider the query:
SELECT data #>> '{address,city}' FROM customers;
If this query returns NULL unexpectedly, what is the most likely cause?

AThe path '{address,city}' does not exist in some JSON rows

BThe operator #>> is used incorrectly and should be #>

CThe JSON column is not valid JSON format

DThe query syntax is invalid

Step-by-Step Solution

Solution:

Step 1: Understand NULL from JSON path extraction
If the specified path does not exist in the JSON data, the operator returns NULL.
Step 2: Check other options
The syntax is correct; #>> is valid for text extraction; invalid JSON would cause errors, not NULL.
Final Answer:
The path '{address,city}' does not exist in some JSON rows -> Option A
Quick Check:
Missing path returns NULL [OK]

Quick Trick: NULL means path missing, not syntax error [OK]

Common Mistakes:

Assuming syntax error causes NULL
Confusing #> and #>> usage
Ignoring missing keys in JSON

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Consider the query:

Step 1: Understand NULL from JSON path extraction

Step 2: Check other options

Final Answer:

Quick Check:

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