AP 11 - Avoid implicit column references
Severity
WarningType
Readability
Correctness
Problem
Don’t use implicit columns references in queries with multiple table joins.
SELECT col3
,col4
FROM tableA a
JOIN tableB b
ON col1=col2
In the example above it is not clear if the columns col1, col2, col3, col4 belong to tableA or tableB. Readability suffers and you increase the risk of introducing bugs in the code.
Solution
Explicitly reference each column
SELECT a.col3
,b.col4
FROM tableA a
JOIN tableB b
ON a.col1=b.col2
In this example each column is referenced by its table alias.
Legitimate use of the anti pattern
If you only have one table in your query you can use implicit column references.