fix convert toString

Author: mj-db

src/main/java/net/sf/jsqlparser/statement/alter/AlterExpression.java

@@ -196,7 +196,7 @@ public boolean isOnDeleteCascade() {
     /**
      * @param onDeleteCascade
      * @deprecated use
-     *             {@link #setReferentialAction(ReferentialAction.Type, ReferentialAction.Action, boolean)}
+     * {@link #setReferentialAction(ReferentialAction.Type, ReferentialAction.Action, boolean)}
      */
     @Deprecated
     public void setOnDeleteCascade(boolean onDeleteCascade) {
@@ -216,7 +216,7 @@ public boolean isOnDeleteRestrict() {
     /**
      * @param onDeleteRestrict
      * @deprecated use
-     *             {@link #setReferentialAction(ReferentialAction.Type, ReferentialAction.Action, boolean)}
+     * {@link #setReferentialAction(ReferentialAction.Type, ReferentialAction.Action, boolean)}
      */
     @Deprecated
     public void setOnDeleteRestrict(boolean onDeleteRestrict) {
@@ -236,7 +236,7 @@ public boolean isOnDeleteSetNull() {
     /**
      * @param onDeleteSetNull
      * @deprecated use
-     *             {@link #setReferentialAction(ReferentialAction.Type, ReferentialAction.Action, boolean)}
+     * {@link #setReferentialAction(ReferentialAction.Type, ReferentialAction.Action, boolean)}
      */
     @Deprecated
     public void setOnDeleteSetNull(boolean onDeleteSetNull) {
@@ -485,6 +485,14 @@ public String toString() {
         } else if (operation == AlterOperation.DROP_PRIMARY_KEY) {
 
             b.append("DROP PRIMARY KEY ");
+        } else if (operation == AlterOperation.CONVERT) {
+            b.append("CONVERT TO CHARACTER SET ");
+            if (getCharacterSet() != null) {
+                b.append(getCharacterSet());
+            }
+            if (getCollation() != null) {
+                b.append(" COLLATE ").append(getCollation());
+            }
         } else if (operation == AlterOperation.DROP_UNIQUE) {
 
             b.append("DROP UNIQUE (").append(PlainSelect.getStringList(pkColumns)).append(')');

src/test/java/net/sf/jsqlparser/statement/alter/AlterTest.java

@@ -30,7 +30,6 @@
 import java.util.List;
 
 import static net.sf.jsqlparser.test.TestUtils.*;
-import static net.sf.jsqlparser.test.TestUtils.assertSqlCanBeParsedAndDeparsed;
 import static org.junit.jupiter.api.Assertions.*;
 
 public class AlterTest {
@@ -835,7 +834,7 @@ public void testAlterTableDefaultValueTrueIssue926() throws JSQLParserException
     }
 
     private void assertReferentialActionOnConstraint(Alter parsed, Action onUpdate,
-            Action onDelete) {
+                                                     Action onDelete) {
         AlterExpression alterExpression = parsed.getAlterExpressions().get(0);
         ForeignKeyIndex index = (ForeignKeyIndex) alterExpression.getIndex();
 
@@ -1112,7 +1111,7 @@ public void testIssue2089() throws JSQLParserException {
     }
 
     @Test
-    public void testIssue2089WithCollation() throws JSQLParserException {
+    public void testIssue2089ConvertWithCollation() throws JSQLParserException {
         String sql =
                 "ALTER TABLE test_table CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci";
         Statement stmt = CCJSqlParserUtil.parse(sql);
@@ -1128,6 +1127,8 @@ public void testIssue2089WithCollation() throws JSQLParserException {
         assertEquals(AlterOperation.CONVERT, convertExp.getOperation());
         assertEquals("utf8mb4", convertExp.getCharacterSet());
         assertEquals("utf8mb4_general_ci", convertExp.getCollation());
+
+        assertSqlCanBeParsedAndDeparsed(sql);
     }
 
     @Test