xuzifu666 commented on code in PR #5052:
URL: https://github.com/apache/calcite/pull/5052#discussion_r3484959925


##########
core/src/test/resources/sql/agg.iq:
##########
@@ -4301,4 +4301,29 @@ GROUP BY GROUPING SETS ((deptno), ());
 
 !ok
 
+# [CALCITE-6104] Aggregate function that references outer column should be 
evaluated in outer query

Review Comment:
   Thanks for the reminder, I had added comment about it and the test case had 
been added. 
   But agg.iq to verify the correctness of the numerical results calculated 
after the Calcite fix within PostgreSQL, the original SQL must be rewritten 
into standard SQL supported by PostgreSQL.
   Validated these sql in https://onecompiler.com/postgresql/44tgmwq6p  and 
result is as expected.



##########
core/src/main/java/org/apache/calcite/sql/validate/SqlValidatorImpl.java:
##########
@@ -5658,6 +5665,251 @@ protected RelDataType validateSelectList(final 
SqlNodeList selectItems,
     return typeFactory.createStructType(fieldList);
   }
 
+  /**
+   * Rewrites scalar sub-queries in the SELECT list whose single select item is
+   * an aggregate function whose arguments reference only outer columns. Per 
the
+   * SQL standard, such aggregates belong to the outer query.
+   *
+   * <p>For example,
+   * <blockquote><pre>SELECT (SELECT sum(a) FROM t LIMIT 1) FROM 
aa</pre></blockquote>
+   * is rewritten to
+   * <blockquote><pre>SELECT sum(a) * (SELECT 1 FROM t LIMIT 1) FROM 
aa</pre></blockquote>

Review Comment:
   Okay, I’ve added the logic for the overall process; I hope that clarifies 
things.



##########
core/src/test/resources/sql/agg.iq:
##########
@@ -4301,4 +4301,29 @@ GROUP BY GROUPING SETS ((deptno), ());
 
 !ok
 
+# [CALCITE-6104] Aggregate function that references outer column should be 
evaluated in outer query
+WITH aa (a) AS (VALUES 1, 2, 3),
+  xx (x) AS (VALUES 10, 20, 30)
+SELECT (SELECT sum(a) FROM xx LIMIT 1) AS sa
+FROM aa;
++----+
+| SA |
++----+
+|  6 |
++----+
+(1 row)
+
+!ok
+
+SELECT (SELECT sum(sal) FROM dept) AS sum_sal

Review Comment:
   Yes, I review the blog overall and add new case for it. The correspondence 
is as follows:
   ```
   SELECT (SELECT sum(1) FROM xx LIMIT 1) FROM aa
   ```
   Aggregate with no column references aggregates at the innermost level.
   
   ```
   SELECT (SELECT sum(a) FROM xx LIMIT 1) FROM aa
   ```
   Aggregate function that references outer column should be evaluated in outer 
query.
   
   ```
   SELECT (SELECT sum(x) FROM xx LIMIT 1) FROM aa
   ```
   Aggregate referencing only inner column aggregates at the inner level.



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