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Table.SelectColumns

返回只含有指定列的表。

Syntax​

Table.SelectColumns(
    table as table,
    columns as any,
    optional missingField as MissingField.Type
) as table

Remarks​

返回仅具有指定 table 的 columns。

  • table: 提供的表。
  • columns: 要返回的表 table 中列的列表。返回表中的列按 columns 中列出的顺序。
  • missingField: *(可选)*列不存在时如何操作。 示例: MissingField.UseNull 或 MissingField.Ignore。

Examples​

Example #1​

只包含列 [Name]。

Table.SelectColumns(
    Table.FromRecords({
        [CustomerID = 1, Name = "Bob", Phone = "123-4567"],
        [CustomerID = 2, Name = "Jim", Phone = "987-6543"],
        [CustomerID = 3, Name = "Paul", Phone = "543-7890"],
        [CustomerID = 4, Name = "Ringo", Phone = "232-1550"]
    }),
    "Name"
)

Result:

Table.FromRecords({
    [Name = "Bob"],
    [Name = "Jim"],
    [Name = "Paul"],
    [Name = "Ringo"]
})

Example #2​

只包含列 [CustomerID] 和列 [Name]。

Table.SelectColumns(
    Table.FromRecords({[CustomerID = 1, Name = "Bob", Phone = "123-4567"]}),
    {"CustomerID", "Name"}
)

Result:

Table.FromRecords({[CustomerID = 1, Name = "Bob"]})

Example #3​

如果包含的列没有退出，则默认结果为错误。

Table.SelectColumns(
    Table.FromRecords({[CustomerID = 1, Name = "Bob", Phone = "123-4567"]}),
    "NewColumn"
)

Result:

[Expression.Error] The field 'NewColumn' of the record wasn't found.

Example #4​

如果包含的列没有退出，选项 MissingField.UseNull 将创建包含 null 值的列。

Table.SelectColumns(
    Table.FromRecords({[CustomerID = 1, Name = "Bob", Phone = "123-4567"]}),
    {"CustomerID", "NewColumn"},
    MissingField.UseNull
)

Result:

Table.FromRecords({[CustomerID = 1, NewColumn = null]})

Category​

Table.Column operations