From 1461eeaacc3f63c6b660b981ae894e70738cd354 Mon Sep 17 00:00:00 2001 From: deardrops Date: Wed, 11 Mar 2020 20:38:12 +0800 Subject: [PATCH] sql: clarify unsupported behavior in generated column --- reference/sql/generated-columns.md | 2 ++ 1 file changed, 2 insertions(+) diff --git a/reference/sql/generated-columns.md b/reference/sql/generated-columns.md index b217d628ab735..81fe446767f1d 100644 --- a/reference/sql/generated-columns.md +++ b/reference/sql/generated-columns.md @@ -80,4 +80,6 @@ CREATE TABLE person ( The current limitations of JSON and generated columns are as follows: - You cannot add the generated column in the storage type of `STORED` through `ALTER TABLE`. +- You can neither convert a generated stored column to a normal column through the `ALTER TABLE` statement nor convert a normal column to a generated stored column. +- You cannot modify the **expression** of a generated stored column through the `ALTER TABLE` statement. - Not all [JSON functions](/reference/sql/functions-and-operators/json-functions.md) are supported.