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Posted to issues@calcite.apache.org by "Dominik Labuda (Jira)" <ji...@apache.org> on 2021/02/08 18:53:00 UTC
[jira] [Updated] (CALCITE-4491) Aggregation of window function
produces invalid SQL for PostgreSQL
[ https://issues.apache.org/jira/browse/CALCITE-4491?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Dominik Labuda updated CALCITE-4491:
------------------------------------
Description:
h2. Issue
We tested the following behavior against PostgreSQL database, however more of the supported dialects may be affected.
When aggregating the results of a window function an invalid SQL is generated. I was able to replicate the behavior in tests with:
{code:java}
@Test void testAggregatingWindowFunction() {
final RelBuilder builder = relBuilder();
final RelNode root = builder
.scan("EMP")
.project(
builder.alias(
builder.getRexBuilder().makeOver(
builder.getTypeFactory().createSqlType(SqlTypeName.INTEGER),
SqlStdOperatorTable.RANK,
new ArrayList<>(),
new ArrayList<>(),
ImmutableList.of(new RexFieldCollation(builder.field("SAL"), ImmutableSet.of())),
RexWindowBounds.UNBOUNDED_PRECEDING,
RexWindowBounds.UNBOUNDED_FOLLOWING,
true,
true,
false,
false,
false
),
"rank"
)
)
.as("tmp")
.aggregate(
builder.groupKey(),
builder.count(
true,
"cnt",
builder.field("tmp", "rank")
)
)
.build();
final String expectedSql = "SELECT COUNT(DISTINCT \"rank\") AS \"cnt\"\n" +
"FROM (SELECT RANK() OVER (ORDER BY \"SAL\") AS \"rank\"\n" +
"FROM \"scott\".\"EMP\") AS \"t\"";
assertThat(
toSql(root, PostgresqlSqlDialect.DEFAULT),
isLinux(expectedSql)
);
}
{code}
The code above fails, since it produces this SQL instead of the expected one, which cannot be executed on PGSQL:
{noformat}
SELECT COUNT(DISTINCT RANK() OVER (ORDER BY "SAL")) AS "cnt"
FROM "scott"."EMP"
{noformat}
In that case I am getting this kinds of errors from DB:
{noformat}
ERROR: aggregate function calls cannot contain window function calls
{noformat}
h2. Suggested solution
Since _SqlDialect_ already contains support for determining whether the databases support nested aggregations via _public boolean supportsNestedAggregations()_ we could either add another method like _public boolean supportsNestedWindows()_ maybe _supportNestedWindowsInAggregation()_ to be more verbose. Or we could reuse the existing method for the window purposes (which seems non-transparent). Then we will be able to handle the behavior in _SqlImplementor.needNewSubQuery()_ similarly as it already does with the aggregations.
Please let me know if you agree and I will be more than happy to provide you with PR to review, thanks!
was:
h2. Issue
We tested the following behavior against PostgreSQL database, however more of the supported dialects may be affected.
When aggregating the results of a window function an invalid SQL is generated. I was able to replicate the behavior in tests with:
{code:java}
@Test void testAggregatingWindowFunction() {
final RelBuilder builder = relBuilder();
final RelNode root = builder
.scan("EMP")
.project(
builder.alias(
builder.getRexBuilder().makeOver(
builder.getTypeFactory().createSqlType(SqlTypeName.INTEGER),
SqlStdOperatorTable.RANK,
new ArrayList<>(),
new ArrayList<>(),
ImmutableList.of(new RexFieldCollation(builder.field("SAL"), ImmutableSet.of())),
RexWindowBounds.UNBOUNDED_PRECEDING,
RexWindowBounds.UNBOUNDED_FOLLOWING,
true,
true,
false,
false,
false
),
"rank"
)
)
.as("tmp")
.aggregate(
builder.groupKey(),
builder.count(
true,
"cnt",
builder.field("tmp", "rank")
)
)
.build();
final String expectedSql = "SELECT COUNT(DISTINCT \"rank\") AS \"cnt\"\n" +
"FROM (SELECT RANK() OVER (ORDER BY \"SAL\") AS \"rank\"\n" +
"FROM \"scott\".\"EMP\") AS \"t\"";
assertThat(
toSql(root, PostgresqlSqlDialect.DEFAULT),
isLinux(expectedSql)
);
}
{code}
The code above fails, since it produces this SQL instead of the expected one, which cannot be executed on PGSQL:
{noformat}
SELECT COUNT(DISTINCT RANK() OVER (ORDER BY "SAL")) AS "cnt"
FROM "scott"."EMP"
{noformat}
In that case I am getting this kinds of errors from DB:
{noformat}
ERROR: aggregate function calls cannot contain window function calls
{noformat}
h2. Suggested solution
Since _SqlDialect_ already contains support for determining whether the databases support nested aggregations via _public boolean supportsNestedAggregations()_ we could either add another method like _public boolean supportsNestedWindows()_ maybe _supportNestedWindowsInAggregation_ to be more verbose. Or we could reuse the existing method for the window purposes (which seems non-transparent). Then we will be able to handle the behavior in _SqlImplementor.needNewSubQuery()_ similarly as it already does with the aggregations.
Please let me know if you agree and I will be more than happy to provide you with PR to review, thanks!
> Aggregation of window function produces invalid SQL for PostgreSQL
> ------------------------------------------------------------------
>
> Key: CALCITE-4491
> URL: https://issues.apache.org/jira/browse/CALCITE-4491
> Project: Calcite
> Issue Type: Bug
> Components: core
> Affects Versions: 1.26.0
> Reporter: Dominik Labuda
> Priority: Major
>
> h2. Issue
> We tested the following behavior against PostgreSQL database, however more of the supported dialects may be affected.
> When aggregating the results of a window function an invalid SQL is generated. I was able to replicate the behavior in tests with:
> {code:java}
> @Test void testAggregatingWindowFunction() {
> final RelBuilder builder = relBuilder();
> final RelNode root = builder
> .scan("EMP")
> .project(
> builder.alias(
> builder.getRexBuilder().makeOver(
> builder.getTypeFactory().createSqlType(SqlTypeName.INTEGER),
> SqlStdOperatorTable.RANK,
> new ArrayList<>(),
> new ArrayList<>(),
> ImmutableList.of(new RexFieldCollation(builder.field("SAL"), ImmutableSet.of())),
> RexWindowBounds.UNBOUNDED_PRECEDING,
> RexWindowBounds.UNBOUNDED_FOLLOWING,
> true,
> true,
> false,
> false,
> false
> ),
> "rank"
> )
> )
> .as("tmp")
> .aggregate(
> builder.groupKey(),
> builder.count(
> true,
> "cnt",
> builder.field("tmp", "rank")
> )
> )
> .build();
> final String expectedSql = "SELECT COUNT(DISTINCT \"rank\") AS \"cnt\"\n" +
> "FROM (SELECT RANK() OVER (ORDER BY \"SAL\") AS \"rank\"\n" +
> "FROM \"scott\".\"EMP\") AS \"t\"";
> assertThat(
> toSql(root, PostgresqlSqlDialect.DEFAULT),
> isLinux(expectedSql)
> );
> }
> {code}
> The code above fails, since it produces this SQL instead of the expected one, which cannot be executed on PGSQL:
> {noformat}
> SELECT COUNT(DISTINCT RANK() OVER (ORDER BY "SAL")) AS "cnt"
> FROM "scott"."EMP"
> {noformat}
> In that case I am getting this kinds of errors from DB:
> {noformat}
> ERROR: aggregate function calls cannot contain window function calls
> {noformat}
> h2. Suggested solution
> Since _SqlDialect_ already contains support for determining whether the databases support nested aggregations via _public boolean supportsNestedAggregations()_ we could either add another method like _public boolean supportsNestedWindows()_ maybe _supportNestedWindowsInAggregation()_ to be more verbose. Or we could reuse the existing method for the window purposes (which seems non-transparent). Then we will be able to handle the behavior in _SqlImplementor.needNewSubQuery()_ similarly as it already does with the aggregations.
> Please let me know if you agree and I will be more than happy to provide you with PR to review, thanks!
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