From c12f5d23f0699e7335a102499f5a0432aa8f2cd8 Mon Sep 17 00:00:00 2001
From: jipeli <54889677+jipeli@users.noreply.github.com>
Date: Mon, 22 Jan 2024 12:54:45 +0800
Subject: [PATCH] [improvement][headless] fix derived metric case parse error
 (#678)

---
 .../util/jsqlparser/ExpressionReplaceVisitor.java | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/common/src/main/java/com/tencent/supersonic/common/util/jsqlparser/ExpressionReplaceVisitor.java b/common/src/main/java/com/tencent/supersonic/common/util/jsqlparser/ExpressionReplaceVisitor.java
index 950fa5ad7..23044aa46 100644
--- a/common/src/main/java/com/tencent/supersonic/common/util/jsqlparser/ExpressionReplaceVisitor.java
+++ b/common/src/main/java/com/tencent/supersonic/common/util/jsqlparser/ExpressionReplaceVisitor.java
@@ -8,6 +8,7 @@ import net.sf.jsqlparser.expression.BinaryExpression;
 import net.sf.jsqlparser.expression.Expression;
 import net.sf.jsqlparser.expression.ExpressionVisitorAdapter;
 import net.sf.jsqlparser.expression.Function;
+import net.sf.jsqlparser.expression.WhenClause;
 import net.sf.jsqlparser.schema.Column;
 
 public class ExpressionReplaceVisitor extends ExpressionVisitorAdapter {
@@ -19,6 +20,20 @@ public class ExpressionReplaceVisitor extends ExpressionVisitorAdapter {
         this.fieldExprMap = fieldExprMap;
     }
 
+    public void visit(WhenClause expr) {
+        expr.getWhenExpression().accept(this);
+        if (expr.getThenExpression() instanceof Column) {
+            Column column = (Column) expr.getThenExpression();
+            Expression expression = QueryExpressionReplaceVisitor.getExpression(
+                    QueryExpressionReplaceVisitor.getReplaceExpr(column, fieldExprMap));
+            if (Objects.nonNull(expression)) {
+                expr.setThenExpression(expression);
+            }
+        } else {
+            expr.getThenExpression().accept(this);
+        }
+    }
+
     protected void visitBinaryExpression(BinaryExpression expr) {
         Expression left = expr.getLeftExpression();
         Expression right = expr.getRightExpression();