Power BI查询中SWITCH函数未被识别，自定义列表达式报错求助

Looks like you ran into a classic mix-up between DAX and Power Query M language syntax—plus a tiny spelling error that was adding to the confusion. Let's break down what went wrong and fix it:

Key Issues in Your Original Code #

• Wrong SWITCH Syntax for M Language: Unlike DAX, Power Query's SWITCH doesn't use assignment expressions (like Empolyees = "Chris1") in the result branches. You just need to return the value you want the new column to have directly.
• Typos: You misspelled "Employees" as "Empolyees" (missing the letter 'y') in both the new column name and the branch expressions.
• Incorrect Result Structure: Each pairing in M's SWITCH should be [Matching Value], [Result Value], not a conditional assignment.

Corrected Code #

= Table.AddColumn(#"Removed Columns", "Employees", each 
    SWITCH(
        [Index],
        1, "Chris1",
        2, "Chris2",
        3, "Chris3",
        4, "Chris4",
        5, "Chris5",
        6, "Chris6",
        7, "Chris7",
        8, "Chris8",
        BLANK()
    )
)

What Changed? #

1. Fixed the Spelling: Renamed the new column and corrected all references to "Employees" (no more missing 'y').
2. Adjusted SWITCH Branches: Instead of writing Empolyees = "ChrisX", we just return the string value "ChrisX" directly—this is how M language assigns values to the new column.
3. Preserved Valid Structure: Kept the core logic of matching the [Index] column values to your desired names, with BLANK() as the fallback for unlisted index numbers.

A quick reminder: If you were trying to create a DAX calculated column instead of a Power Query custom column, your original syntax would be closer to correct (with the spelling fix), but since you're using Table.AddColumn, we're working in M language here—hence the syntax differences.

内容的提问来源于stack exchange，提问作者Cosq