选择¶

SELECT 语句用于以列的形式选择数据。来自 BodoSQL 的数据存储在一个数据框中。

SELECT <COLUMN_NAMES> FROM <TABLE_NAME>

例如：

SELECT A FROM customers

示例用法:¶

>>>@bodo.jit
... def g(df):
...    bc = bodosql.BodoSQLContext({"CUSTOMERS":df})
...    query = "SELECT name FROM customers"
...    res = bc.sql(query)
...    return res

>>>customers_df = pd.DataFrame({
...     "CUSTOMERID": [0, 1, 2, 3, 4, 5, 6, 7, 8, 9],
...     "NAME": ["Deangelo Todd","Nikolai Kent","Eden Heath", "Taliyah Martinez",
...                 "Demetrius Chavez","Weston Jefferson","Jonathon Middleton",
...                 "Shawn Winters","Keely Hutchinson", "Darryl Rosales",],
...     "BALANCE": [1123.34, 2133.43, 23.58, 8345.15, 943.43, 68.34, 12764.50, 3489.25, 654.24, 25645.39]
... })

>>>g(customers_df)
                NAME
0       Deangelo Todd
1        Nikolai Kent
2          Eden Heath
3    Taliyah Martinez
4    Demetrius Chavez
5    Weston Jefferson
6  Jonathon Middleton
7       Shawn Winters
8    Keely Hutchinson
9      Darryl Rosales

SELECT 也有一些特殊的语法形式。* 用作指定所有列的快捷方式。* EXCLUDE col 或 * EXCLUDE (col1, col2, col3...) 是指定除了 EXCLUDE 关键字之后的列以外的每一列的快捷方式。

例如，假设我们有一个表 The T，它的列名为 The A、B、C、D、E。考虑以下查询

SELECT * FROM T

SELECT * EXCLUDE (A, E) FROM T

这两个是以下内容的语法糖：

SELECT A, B, C, D, E FROM T

SELECT B, C, D FROM T