RocMarshal commented on a change in pull request #16418:
URL: https://github.com/apache/flink/pull/16418#discussion_r667493819
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File path: docs/content.zh/docs/dev/table/sql/queries/select.md
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@@ -22,41 +22,41 @@ specific language governing permissions and limitations
under the License.
-->
-# SELECT & WHERE clause
+# SELECT 与 WHERE 子句
{{< label Batch >}} {{< label Streaming >}}
-The general syntax of the `SELECT` statement is:
+`SELECT` 语句的常见语法格式如下所示:
```sql
SELECT select_list FROM table_expression [ WHERE boolean_expression ]
```
-The `table_expression` refers to any source of data. It could be an existing
table, view, or `VALUES` clause, the joined results of multiple existing
tables, or a subquery. Assuming that the table is available in the catalog, the
following would read all rows from `Orders`.
+这里的 `table_expression` 可以是任意的数据来源。它可以是一张已经存在的表、视图或者 `VALUES`
子句，也可以是多个现有表的关联结果、或一个子查询。这里我们假设 `Orders` 表在 `Catalog` 中处于可用状态，那么下面的语句会从
`Orders` 表中读出所有的行。
```sql
SELECT * FROM Orders
```
-The `select_list` specification `*` means the query will resolve all columns.
However, usage of `*` is discouraged in production because it makes queries
less robust to catalog changes. Instead, a `select_list` can specify a subset
of available columns or make calculations using said columns. For example, if
`Orders` has columns named `order_id`, `price`, and `tax` you could write the
following query:
+在 `select_list` 处的 `*` 表示查询操作将会解析所有列。但是，我们不鼓励在生产中使用 `*`，因为它会使查询操作在应对 `Catalog`
变化的时候鲁棒性降低。相反，可以在 `select_list` 处指定可用列的子集，或者使用声明的列进行计算。例如，假设 `Orders` 表中有名为
`order_id`、`price` 和 `tax` 的列，那么你可以编写如下查询：
```sql
SELECT order_id, price + tax FROM Orders
```
-Queries can also consume from inline data using the `VALUES` clause. Each
tuple corresponds to one row and an alias may be provided to assign names to
each column.
+查询操作还可以在 `VALUES` 子句中使用内联数据。每一个元组对应一行，另外可以通过设置别名来为每一列指定名称。
```sql
SELECT order_id, price FROM (VALUES (1, 2.0), (2, 3.1)) AS t (order_id, price)
```
-Rows can be filtered based on a `WHERE` clause.
+可以根据 `WHERE` 子句对行数据进行过滤。
```sql
SELECT price + tax FROM Orders WHERE id = 10
```
-Additionally, built-in and [user-defined scalar functions]({{< ref
"docs/dev/table/functions/udfs" >}}) can be invoked on the columns of a single
row. User-defined functions must be registered in a catalog before use.
+此外，在任意一行的列上你可以调用内置函数和[用户自定义标量函数（user-defined scalar functions）]({{< ref
"docs/dev/table/functions/udfs" >}})。当然，在使用前用户自定义函数（ user-defined
functions）必须已经注册到 `Catalog` 中。
Review comment:
So sorry for previous comments.I notice that you typed "\`Catalog\`"
in other parts. So please keep "\`Catalog\`" here for unified style.
Thank you.
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