From ae4c83fd14826271e9a28e7b4c080db0c54c710a Mon Sep 17 00:00:00 2001
From: HangyuanLiu <460660596@qq.com>
Date: Tue, 13 Oct 2020 19:28:36 +0800
Subject: [PATCH 1/2] fix

---
 .../doris/analysis/FunctionCallExpr.java      |  8 ++++++-
 .../apache/doris/planner/QueryPlanTest.java   | 21 +++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java b/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java
index 35873a251c0dba..cc4f496e28a789 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java
@@ -334,11 +334,17 @@ private void analyzeBuiltinAggFunction(Analyzer analyzer) throws AnalysisExcepti
                 throw new AnalysisException(fnName.getFunction() + " only used in analytic function");
             } else {
                 if (children.size() > 2) {
-                    if (!getChild(2).isConstant()) {
+                    if (!getChild(1).isConstant() || !getChild(2).isConstant()) {
                         throw new AnalysisException(
                                 "The default parameter (parameter 3) of LAG must be a constant: "
                                         + this.toSql());
                     }
+                    getChild(1).type = Type.BIGINT;
+                    //To ensure that the correct function is selected,the third parameter
+                    //of the lead function must be consistent with the first parameter
+                    if (!getChild(2).type.matchesType(getChild(0).type) && !getChild(2).type.matchesType(Type.NULL)) {
+                        getChild(2).type = getChild(0).type;
+                    }
                 }
                 return;
             }
diff --git a/fe/fe-core/src/test/java/org/apache/doris/planner/QueryPlanTest.java b/fe/fe-core/src/test/java/org/apache/doris/planner/QueryPlanTest.java
index f2b93fba6934dd..ba3e24ce9572f9 100644
--- a/fe/fe-core/src/test/java/org/apache/doris/planner/QueryPlanTest.java
+++ b/fe/fe-core/src/test/java/org/apache/doris/planner/QueryPlanTest.java
@@ -1310,6 +1310,27 @@ public void testAggregateSatisfyOlapTableDistribution() throws Exception {
         System.out.println(explainString);
         Assert.assertTrue(explainString.contains("AGGREGATE (update finalize)"));
     }
+
+    @Test
+    public void testLeadAndLagFunction() throws Exception {
+        connectContext.setDatabase("default_cluster:test");
+
+        String queryStr = "explain select time, lead(query_time, 1, NULL) over () as time2 from test.test1";
+        String explainString = UtFrameUtils.getSQLPlanOrErrorMsg(connectContext, queryStr);
+        Assert.assertTrue(explainString.contains("lead(`query_time`, 1, NULL)"));
+
+        queryStr = "explain select time, lead(query_time, 1, 2) over () as time2 from test.test1";
+        explainString = UtFrameUtils.getSQLPlanOrErrorMsg(connectContext, queryStr);
+        Assert.assertTrue(explainString.contains("lead(`query_time`, 1, 2)"));
+
+        queryStr = "explain select time, lead(time, 1, '2020-01-01 00:00:00') over () as time2 from test.test1";
+        explainString = UtFrameUtils.getSQLPlanOrErrorMsg(connectContext, queryStr);
+        Assert.assertTrue(explainString.contains("lead(`time`, 1, '2020-01-01 00:00:00')"));
+
+        queryStr = "explain select time, lag(query_time, 1, 2) over () as time2 from test.test1";
+        explainString = UtFrameUtils.getSQLPlanOrErrorMsg(connectContext, queryStr);
+        Assert.assertTrue(explainString.contains("lag(`query_time`, 1, 2)"));
+    }
 }
 
 

From 3b76305bbdf3e078d32d1c2807041daec9dd64f5 Mon Sep 17 00:00:00 2001
From: HangyuanLiu <460660596@qq.com>
Date: Tue, 13 Oct 2020 19:58:05 +0800
Subject: [PATCH 2/2] fix

---
 .../java/org/apache/doris/analysis/FunctionCallExpr.java | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java b/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java
index cc4f496e28a789..d43178d4146d5e 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/analysis/FunctionCallExpr.java
@@ -336,14 +336,11 @@ private void analyzeBuiltinAggFunction(Analyzer analyzer) throws AnalysisExcepti
                 if (children.size() > 2) {
                     if (!getChild(1).isConstant() || !getChild(2).isConstant()) {
                         throw new AnalysisException(
-                                "The default parameter (parameter 3) of LAG must be a constant: "
-                                        + this.toSql());
+                                "The default parameter (parameter 2 or parameter 3) of LEAD/LAG must be a constant: " + this.toSql());
                     }
-                    getChild(1).type = Type.BIGINT;
-                    //To ensure that the correct function is selected,the third parameter
-                    //of the lead function must be consistent with the first parameter
+                    uncheckedCastChild(Type.BIGINT, 1);
                     if (!getChild(2).type.matchesType(getChild(0).type) && !getChild(2).type.matchesType(Type.NULL)) {
-                        getChild(2).type = getChild(0).type;
+                        uncheckedCastChild(getChild(0).type, 2);
                     }
                 }
                 return;