From a6ab6c1cb82b512d27ed57e80fad3760fb104e4d Mon Sep 17 00:00:00 2001
From: minghong <englefly@gmail.com>
Date: Thu, 29 Feb 2024 16:01:01 +0800
Subject: [PATCH] =?UTF-8?q?[fix](nereids)=20stats=20derive=20for=20"not=20?=
 =?UTF-8?q?equal=E2=80=9C,=20avoid=20to=20derive=20zero=20ndv=20(#31566)?=
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---
 .../org/apache/doris/nereids/stats/FilterEstimation.java | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java b/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java
index 496a66f745..f7f8667e70 100644
--- a/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java
+++ b/fe/fe-core/src/main/java/org/apache/doris/nereids/stats/FilterEstimation.java
@@ -24,7 +24,6 @@ import org.apache.doris.nereids.trees.expressions.And;
 import org.apache.doris.nereids.trees.expressions.ComparisonPredicate;
 import org.apache.doris.nereids.trees.expressions.CompoundPredicate;
 import org.apache.doris.nereids.trees.expressions.EqualPredicate;
-import org.apache.doris.nereids.trees.expressions.EqualTo;
 import org.apache.doris.nereids.trees.expressions.Expression;
 import org.apache.doris.nereids.trees.expressions.GreaterThan;
 import org.apache.doris.nereids.trees.expressions.GreaterThanEqual;
@@ -376,9 +375,9 @@ public class FilterEstimation extends ExpressionVisitor<Statistics, EstimationCo
                         "Not-predicate meet unexpected child: %s", child.toSql());
                 if (child instanceof Like) {
                     rowCount = context.statistics.getRowCount() - childStats.getRowCount();
-                    colBuilder.setNdv(originColStats.ndv - childColStats.ndv);
+                    colBuilder.setNdv(Math.max(1.0, originColStats.ndv - childColStats.ndv));
                 } else if (child instanceof InPredicate) {
-                    colBuilder.setNdv(originColStats.ndv - childColStats.ndv);
+                    colBuilder.setNdv(Math.max(1.0, originColStats.ndv - childColStats.ndv));
                     colBuilder.setMinValue(originColStats.minValue)
                             .setMinExpr(originColStats.minExpr)
                             .setMaxValue(originColStats.maxValue)
@@ -389,8 +388,8 @@ public class FilterEstimation extends ExpressionVisitor<Statistics, EstimationCo
                             .setMinExpr(originColStats.minExpr)
                             .setMaxValue(originColStats.maxValue)
                             .setMaxExpr(originColStats.maxExpr);
-                } else if (child instanceof EqualTo) {
-                    colBuilder.setNdv(originColStats.ndv - childColStats.ndv);
+                } else if (child instanceof EqualPredicate) {
+                    colBuilder.setNdv(Math.max(1.0, originColStats.ndv - childColStats.ndv));
                     colBuilder.setMinValue(originColStats.minValue)
                             .setMinExpr(originColStats.minExpr)
                             .setMaxValue(originColStats.maxValue)