EmmyMiao87 commented on a change in pull request #3150: Support non-correlated
subquery in having clause
URL: https://github.com/apache/incubator-doris/pull/3150#discussion_r397577884
##########
File path: fe/src/main/java/org/apache/doris/analysis/StmtRewriter.java
##########
@@ -43,62 +44,260 @@
* Rewrite the statement of an analysis result. The unanalyzed rewritten
* statement is returned.
*/
- public static void rewrite(Analyzer analyzer, StatementBase parsedStmt)
+ public static StatementBase rewrite(Analyzer analyzer, StatementBase
parsedStmt)
throws AnalysisException {
if (parsedStmt instanceof QueryStmt) {
QueryStmt analyzedStmt = (QueryStmt) parsedStmt;
Preconditions.checkNotNull(analyzedStmt.analyzer);
- rewriteQueryStatement(analyzedStmt, analyzer);
+ return rewriteQueryStatement(analyzedStmt, analyzer);
} else if (parsedStmt instanceof InsertStmt) {
final InsertStmt insertStmt = (InsertStmt)parsedStmt;
final QueryStmt analyzedStmt =
(QueryStmt)insertStmt.getQueryStmt();
Preconditions.checkNotNull(analyzedStmt.analyzer);
- rewriteQueryStatement(analyzedStmt, analyzer);
+ QueryStmt rewrittenQueryStmt = rewriteQueryStatement(analyzedStmt,
analyzer);
+ insertStmt.setQueryStmt(rewrittenQueryStmt);
} else {
throw new AnalysisException("Unsupported statement containing
subqueries: "
+ parsedStmt.toSql());
}
+ return parsedStmt;
}
/**
* Calls the appropriate rewrite method based on the specific type of query
stmt. See
* rewriteSelectStatement() and rewriteUnionStatement() documentation.
*/
- public static void rewriteQueryStatement(QueryStmt stmt, Analyzer analyzer)
+ public static QueryStmt rewriteQueryStatement(QueryStmt stmt, Analyzer
analyzer)
throws AnalysisException {
Preconditions.checkNotNull(stmt);
if (stmt instanceof SelectStmt) {
- rewriteSelectStatement((SelectStmt) stmt, analyzer);
+ return rewriteSelectStatement((SelectStmt) stmt, analyzer);
} else if (stmt instanceof SetOperationStmt) {
rewriteUnionStatement((SetOperationStmt) stmt, analyzer);
} else {
throw new AnalysisException("Subqueries not supported for "
+ stmt.getClass().getSimpleName() + " statements");
}
+ return stmt;
}
- private static void rewriteSelectStatement(SelectStmt stmt, Analyzer
analyzer)
+ private static SelectStmt rewriteSelectStatement(SelectStmt stmt, Analyzer
analyzer)
throws AnalysisException {
+ SelectStmt result = stmt;
// Rewrite all the subqueries in the FROM clause.
- for (TableRef tblRef: stmt.fromClause_) {
+ for (TableRef tblRef: result.fromClause_) {
if (!(tblRef instanceof InlineViewRef)) continue;
InlineViewRef inlineViewRef = (InlineViewRef)tblRef;
- rewriteQueryStatement(inlineViewRef.getViewStmt(),
inlineViewRef.getAnalyzer());
+ QueryStmt rewrittenQueryStmt =
rewriteQueryStatement(inlineViewRef.getViewStmt(),
+ inlineViewRef.getAnalyzer());
+ inlineViewRef.setViewStmt(rewrittenQueryStmt);
}
// Rewrite all the subqueries in the WHERE clause.
- if (stmt.hasWhereClause()) {
+ if (result.hasWhereClause()) {
// Push negation to leaf operands.
- stmt.whereClause = Expr.pushNegationToOperands(stmt.whereClause);
+ result.whereClause =
Expr.pushNegationToOperands(result.whereClause);
// Check if we can rewrite the subqueries in the WHERE clause. OR
predicates with
// subqueries are not supported.
- if (hasSubqueryInDisjunction(stmt.whereClause)) {
+ if (hasSubqueryInDisjunction(result.whereClause)) {
throw new AnalysisException("Subqueries in OR predicates are
not supported: "
- + stmt.whereClause.toSql());
+ + result.whereClause.toSql());
}
- rewriteWhereClauseSubqueries(stmt, analyzer);
+ rewriteWhereClauseSubqueries(result, analyzer);
}
- stmt.sqlString_ = null;
- if (LOG.isDebugEnabled()) LOG.debug("rewritten stmt: " + stmt.toSql());
+ // Rewrite all subquery in the having clause
+ if (result.getHavingPred() != null &&
result.getHavingPred().getSubquery() != null) {
+ result = rewriteHavingClauseSubqueries(result, analyzer);
+ }
+ result.sqlString_ = null;
+ if (LOG.isDebugEnabled()) LOG.debug("rewritten stmt: " +
result.toSql());
+ return result;
+ }
+
+ /**
+ * Rewrite having subquery.
+ * Step1: rewrite having subquery to where subquery
+ * Step2: rewrite where subquery
+ * <p>
+ * For example:
+ * select cs_item_sk, sum(cs_sales_price) from catalog_sales a group by
cs_item_sk
+ * having sum(cs_sales_price) >
+ * (select min(cs_sales_price) from catalog_sales b where
a.cs_item_sk = b.cs_item_sk);
+ * <p>
+ * Step1: rewrite having subquery to where subquery
+ * Outer query is changed to inline view in rewritten query
+ * Inline view of outer query:
+ * from (select cs_item_sk, sum(cs_sales_price) sum_cs_sales_price
from catalog_sales group by cs_item_sk) a
+ * Rewritten subquery of expr:
+ * where a.sum_cs_sales_price >
+ * (select min(cs_sales_price) from catalog_sales b where
a.cs_item_sk = b.cs_item_sk)
+ * Rewritten query:
+ * select cs_item_sk, a.sum_cs_sales_price from
+ * (select cs_item_sk, sum(cs_sales_price) sum_cs_sales_price from
catalog_sales group by cs_item_sk) a
+ * where a.sum_cs_sales_price >
+ * (select min(cs_sales_price) from catalog_sales b where
a.cs_item_sk = b.cs_item_sk)
+ * <p>
+ * Step2: rewrite where subquery
+ * Inline view of subquery:
+ * from (select b.cs_item_sk, min(cs_sales_price) from catalog_sales b
group by cs_item_sk) c
+ * Rewritten correlated predicate:
+ * where c.cs_item_sk = a.cs_item_sk and a.sum_cs_sales_price >
c.min(cs_sales_price)
+ * The final stmt:
+ * select a.cs_item_sk, a.sum_cs_sales_price from
+ * (select cs_item_sk, sum(cs_sales_price) sum_cs_sales_price from
catalog_sales group by cs_item_sk) a
+ * join
+ * (select b.cs_item_sk, min(b.cs_sales_price) min_cs_sales_price from
catalog_sales b group by b.cs_item_sk) c
+ * where c.cs_item_sk = a.cs_item_sk and a.sum_cs_sales_price >
c.min_cs_sales_price;
+ *
+ * @param stmt
+ * @param analyzer
+ */
+ private static SelectStmt rewriteHavingClauseSubqueries(SelectStmt stmt,
Analyzer analyzer) throws AnalysisException {
+ // prepare parameters
+ SelectList selectList = stmt.getSelectList();
+ List<String> columnLables = stmt.getColLabels();
+ Expr havingClause = stmt.getHavingClauseAfterAnaylzed();
+ List<FunctionCallExpr> aggregateExprs =
stmt.getAggInfo().getAggregateExprs();
+ Preconditions.checkState(havingClause != null);
+ Preconditions.checkState(havingClause.getSubquery() != null);
+ List<OrderByElement> orderByElements =
stmt.getOrderByElementsAfterAnalyzed();
+ long limit = stmt.getLimit();
+ TableAliasGenerator tableAliasGenerator =
stmt.getTableAliasGenerator();
+
+ /*
+ * The outer query is changed to inline view without having predicate
+ * For example:
+ * Query: select cs_item_sk, sum(cs_sales_price) from catalog_sales a
group by cs_item_sk having ...;
+ * Inline view:
+ * from (select cs_item_sk $ColumnA, sum(cs_sales_price) $ColumnB
from catalog_sales a group by cs_item_sk) $TableA
Review comment:
I am afraid of missing understanding.
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