diff --git a/jOOQ/src/main/java/org/jooq/AlterTableAlterStep.java b/jOOQ/src/main/java/org/jooq/AlterTableAlterStep.java
index 833e38a0ed..0fb1a8ffe2 100644
--- a/jOOQ/src/main/java/org/jooq/AlterTableAlterStep.java
+++ b/jOOQ/src/main/java/org/jooq/AlterTableAlterStep.java
@@ -167,13 +167,13 @@ public interface AlterTableAlterStep<T> {
      * Make the column <code>NOT NULL</code>.
      */
     @NotNull @CheckReturnValue
-    @Support({ DERBY, DUCKDB, FIREBIRD, H2, HSQLDB, POSTGRES, YUGABYTEDB })
+    @Support({ DERBY, DUCKDB, FIREBIRD, H2, HSQLDB, MARIADB, POSTGRES, YUGABYTEDB })
     AlterTableFinalStep setNotNull();
 
     /**
      * Make the column nullable.
      */
     @NotNull @CheckReturnValue
-    @Support({ DERBY, DUCKDB, FIREBIRD, H2, HSQLDB, POSTGRES, YUGABYTEDB })
+    @Support({ DERBY, DUCKDB, FIREBIRD, H2, HSQLDB, MARIADB, POSTGRES, YUGABYTEDB })
     AlterTableFinalStep dropNotNull();
 }
diff --git a/jOOQ/src/main/java/org/jooq/AlterTableStep.java b/jOOQ/src/main/java/org/jooq/AlterTableStep.java
index 04630997df..a5baf5159d 100644
--- a/jOOQ/src/main/java/org/jooq/AlterTableStep.java
+++ b/jOOQ/src/main/java/org/jooq/AlterTableStep.java
@@ -251,6 +251,10 @@ public interface AlterTableStep {
      * Add an <code>ALTER COLUMN</code> clause to the <code>ALTER TABLE</code>
      * statement.
      * <p>
+     * Note that in some RDBMS, the current column type is required in order to
+     * alter a column, so for best results, better pass it explicitly with
+     * {@link #alter(Field)}.
+     * <p>
      * This is an alias for {@link #alterColumn(Name)}
      */
     @NotNull @CheckReturnValue
@@ -261,6 +265,10 @@ public interface AlterTableStep {
      * Add an <code>ALTER COLUMN</code> clause to the <code>ALTER TABLE</code>
      * statement.
      * <p>
+     * Note that in some RDBMS, the current column type is required in order to
+     * alter a column, so for best results, better pass it explicitly with
+     * {@link #alter(Field)}.
+     * <p>
      * This is an alias for {@link #alterColumn(String)}
      */
     @NotNull @CheckReturnValue
@@ -278,6 +286,10 @@ public interface AlterTableStep {
     /**
      * Add an <code>ALTER COLUMN</code> clause to the <code>ALTER TABLE</code>
      * statement.
+     * <p>
+     * Note that in some RDBMS, the current column type is required in order to
+     * alter a column, so for best results, better pass it explicitly with
+     * {@link #alterColumn(Field)}.
      */
     @NotNull @CheckReturnValue
     @Support({ CLICKHOUSE, CUBRID, DERBY, DUCKDB, FIREBIRD, H2, HSQLDB, MARIADB, MYSQL, POSTGRES, TRINO, YUGABYTEDB })
@@ -286,6 +298,10 @@ public interface AlterTableStep {
     /**
      * Add an <code>ALTER COLUMN</code> clause to the <code>ALTER TABLE</code>
      * statement.
+     * <p>
+     * Note that in some RDBMS, the current column type is required in order to
+     * alter a column, so for best results, better pass it explicitly with
+     * {@link #alterColumn(Field)}.
      */
     @NotNull @CheckReturnValue
     @Support({ CLICKHOUSE, CUBRID, DERBY, DUCKDB, FIREBIRD, H2, HSQLDB, MARIADB, MYSQL, POSTGRES, TRINO, YUGABYTEDB })
diff --git a/jOOQ/src/main/java/org/jooq/impl/AlterTableImpl.java b/jOOQ/src/main/java/org/jooq/impl/AlterTableImpl.java
index 32206e5db0..7df86dd178 100644
--- a/jOOQ/src/main/java/org/jooq/impl/AlterTableImpl.java
+++ b/jOOQ/src/main/java/org/jooq/impl/AlterTableImpl.java
@@ -1622,6 +1622,16 @@ implements
 
 
 
+                    // [#18043] Assuming users provide explicit data types of the existing column, we can reference it again
+
+
+                    case MARIADB:
+                    case MYSQL:
+                        ctx.sql(' ');
+                        toSQLDDLTypeDeclaration(ctx, alterColumn.getDataType());
+                        ctx.sql(' ').visit(alterColumnNullability.nullable() ? K_NULL : K_NOT_NULL);
+                        break;
+
                     default:
                         ctx.sql(' ').visit(alterColumnNullability.nullable() ? K_DROP_NOT_NULL : K_SET_NOT_NULL);
                         break;