From b8fa22ddd32426cf5268f09f2c761d5c3ac2c1ae Mon Sep 17 00:00:00 2001
From: chenhao7253886 <510341142@qq.com>
Date: Mon, 12 Mar 2018 18:11:54 +0800
Subject: [PATCH] distinguish limit 0 in analyze (#186)

---
 fe/src/com/baidu/palo/analysis/LimitElement.java |  6 ++++++
 fe/src/com/baidu/palo/analysis/QueryStmt.java    | 11 ++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/fe/src/com/baidu/palo/analysis/LimitElement.java b/fe/src/com/baidu/palo/analysis/LimitElement.java
index 10c6056dde47d6..6443d8f582836c 100644
--- a/fe/src/com/baidu/palo/analysis/LimitElement.java
+++ b/fe/src/com/baidu/palo/analysis/LimitElement.java
@@ -91,7 +91,13 @@ public String toSql() {
         sb.append("" + limit);
         return sb.toString();
     }
+
+    public void analyze(Analyzer analyzer) {
+        if (limit == 0) analyzer.setHasEmptyResultSet();
+    }
     
     public void reset() {
+        limit = -1;
+        offset = 0;
     }
 }
diff --git a/fe/src/com/baidu/palo/analysis/QueryStmt.java b/fe/src/com/baidu/palo/analysis/QueryStmt.java
index fd11ec36cfceb3..84361697263269 100644
--- a/fe/src/com/baidu/palo/analysis/QueryStmt.java
+++ b/fe/src/com/baidu/palo/analysis/QueryStmt.java
@@ -110,10 +110,19 @@ public abstract class QueryStmt extends StatementBase {
     public void analyze(Analyzer analyzer) throws AnalysisException, InternalException {
         if (isAnalyzed()) return;
         super.analyze(analyzer);
-        // analyzeLimit(analyzer);
+        analyzeLimit(analyzer);
         if (hasWithClause()) withClause_.analyze(analyzer);
     }
 
+    private void analyzeLimit(Analyzer analyzer) throws AnalysisException {
+        // TODO chenhao
+        if (limitElement.getOffset() > 0 && !hasOrderByClause()) {
+          throw new AnalysisException("OFFSET requires an ORDER BY clause: " +
+                  limitElement.toSql().trim());
+        }
+        limitElement.analyze(analyzer);
+    }
+
     /**
      * Returns a list containing all the materialized tuple ids that this stmt is
      * correlated with (i.e., those tuple ids from outer query blocks that TableRefs