Validate every UPDATE assignment through shared UpdateSet traversal

src/main/java/net/sf/jsqlparser/util/validation/validator/AbstractValidator.java

@@ -10,6 +10,9 @@
 package net.sf.jsqlparser.util.validation.validator;
 
 import net.sf.jsqlparser.expression.Expression;
+import net.sf.jsqlparser.statement.update.UpdateSet;
+import net.sf.jsqlparser.statement.select.Select;
+import net.sf.jsqlparser.statement.select.SelectVisitor;
 import net.sf.jsqlparser.parser.feature.Feature;
 import net.sf.jsqlparser.statement.select.FromItem;
 import net.sf.jsqlparser.statement.select.OrderByElement;
@@ -137,6 +140,25 @@ protected void validateOptionalExpression(Expression expression, ExpressionValid
         validateOptional(expression, e -> e.accept(v, null));
     }
 
+    protected void validateOptionalUpdateSets(List<UpdateSet> updateSets) {
+        if (updateSets != null) {
+            for (UpdateSet updateSet : updateSets) {
+                validateOptionalExpressions(updateSet.getColumns());
+                if (updateSet.getValues() != null) {
+                    for (Expression value : updateSet.getValues()) {
+                        if (value instanceof Select) {
+                            ((Select) value).accept(
+                                    (SelectVisitor<Void>) getValidator(SelectValidator.class),
+                                    null);
+                        } else {
+                            validateOptionalExpression(value);
+                        }
+                    }
+                }
+            }
+        }
+    }
+
     protected void validateOptionalExpressions(List<? extends Expression> expressions) {
         validateOptionalList(expressions, () -> getValidator(ExpressionValidator.class),
                 (o, v) -> o.accept(v, null));

src/main/java/net/sf/jsqlparser/util/validation/validator/MergeValidator.java

@@ -12,7 +12,6 @@
 import net.sf.jsqlparser.parser.feature.Feature;
 import net.sf.jsqlparser.statement.merge.*;
 import net.sf.jsqlparser.statement.select.OptionHint;
-import net.sf.jsqlparser.statement.update.UpdateSet;
 import net.sf.jsqlparser.util.validation.ValidationCapability;
 
 /**
@@ -59,10 +58,7 @@ public void visit(MergeDelete mergeDelete) {
     @Override
     public <S> Void visit(MergeUpdate mergeUpdate, S context) {
         validateOptionalExpression(mergeUpdate.getAndPredicate());
-        for (UpdateSet updateSet : mergeUpdate.getUpdateSets()) {
-            validateOptionalExpressions(updateSet.getColumns());
-            validateOptionalExpressions(updateSet.getValues());
-        }
+        validateOptionalUpdateSets(mergeUpdate.getUpdateSets());
         validateOptionalExpression(mergeUpdate.getDeleteWhereCondition());
         validateOptionalExpression(mergeUpdate.getWhereCondition());
         return null;

src/main/java/net/sf/jsqlparser/util/validation/validator/UpdateValidator.java

@@ -10,7 +10,6 @@
 package net.sf.jsqlparser.util.validation.validator;
 
 import net.sf.jsqlparser.parser.feature.Feature;
-import net.sf.jsqlparser.statement.select.SelectVisitor;
 import net.sf.jsqlparser.statement.select.OptionHint;
 import net.sf.jsqlparser.statement.update.Update;
 import net.sf.jsqlparser.util.validation.ValidationCapability;
@@ -27,7 +26,6 @@ public void validate(Update update) {
             validateFeature(c, Feature.update);
             validateOptionalFeature(c, update.getFromItem(), Feature.updateFrom);
             validateOptionalFeature(c, update.getStartJoins(), Feature.updateJoins);
-            validateFeature(c, update.isUseSelect(), Feature.updateUseSelect);
             validateOptionalFeature(c, update.getOrderByElements(), Feature.updateOrderBy);
             validateOptionalFeature(c, update.getLimit(), Feature.updateLimit);
             validateOptionalFeature(c, update.getReturningClause(),
@@ -41,14 +39,7 @@ public void validate(Update update) {
         validateOptional(update.getStartJoins(),
                 j -> getValidator(SelectValidator.class).validateOptionalJoins(j));
 
-        if (update.isUseSelect()) {
-            validateOptionalExpressions(update.getColumns());
-            validateOptional(update.getSelect(),
-                    e -> e.accept((SelectVisitor<Void>) getValidator(SelectValidator.class), null));
-        } else {
-            validateOptionalExpressions(update.getColumns());
-            validateOptionalExpressions(update.getExpressions());
-        }
+        validateOptionalUpdateSets(update.getUpdateSets());
 
         if (update.getFromItem() != null) {
             validateOptionalFromItem(update.getFromItem());

src/test/java/net/sf/jsqlparser/util/validation/validator/UpdateSetValidationTest.java

@@ -0,0 +1,44 @@
+/*-
+ * #%L
+ * JSQLParser library
+ * %%
+ * Copyright (C) 2004 - 2026 JSQLParser
+ * %%
+ * Dual licensed under GNU LGPL 2.1 or Apache License 2.0
+ * #L%
+ */
+package net.sf.jsqlparser.util.validation.validator;
+
+import net.sf.jsqlparser.parser.feature.Feature;
+import net.sf.jsqlparser.util.validation.ValidationTestAsserts;
+import net.sf.jsqlparser.util.validation.feature.FeaturesAllowed;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+class UpdateSetValidationTest extends ValidationTestAsserts {
+    @ParameterizedTest
+    @ValueSource(strings = {"UPDATE t SET a = ?, b = 1", "UPDATE t SET a = 1, b = ?",
+            "UPDATE t SET a = 1, b = ?, c = 3", "UPDATE t SET a = 1, b = 2, c = ?",
+            "UPDATE t SET (b, c) = (2, ?), a = 1",
+            "UPDATE t SET a = 1, b = (SELECT x FROM s WHERE x = ?)",
+            "MERGE INTO t USING s ON t.id = s.id WHEN MATCHED THEN UPDATE SET a = 1, b = ?"})
+    void validatesValuesInEveryAssignment(String sql) {
+        validateNotAllowed(sql, 1, 1, FeaturesAllowed.DML.copy().remove(Feature.jdbcParameter),
+                Feature.jdbcParameter);
+        validateNoErrors(sql, 1, FeaturesAllowed.DML.copy().add(FeaturesAllowed.JDBC));
+    }
+
+    @Test
+    void reportsIndependentFeaturesAcrossDifferentAssignments() {
+        validateNotAllowed("UPDATE t SET a = 1, b = COALESCE(c, 0), d = ?", 1, 1,
+                FeaturesAllowed.UPDATE.copy().remove(Feature.function, Feature.jdbcParameter),
+                Feature.function, Feature.jdbcParameter);
+    }
+
+    @Test
+    void keepsTupleAndSubqueryAssignmentsValid() {
+        validateNoErrors("UPDATE t SET (a, b) = (SELECT c, d FROM s), e = 1", 1,
+                FeaturesAllowed.UPDATE);
+    }
+}