部分資料來源 (例如 Google Analytics 和 Google Ads) 會將「自動」顯示為指標的唯一可用匯總類型。這些資料集已匯總，將可能龐大的數字清單縮減為單一值。使用的匯總功能可以是簡單的總和或計數，也可以是較複雜的百分位數。您無法將自動匯總指標變更為其他匯總類型，因為這樣做會要求 Looker Studio 存取未匯總的原始資料。
您也會看到系統根據其他資料來源 (例如 Google 試算表) 將自動匯總功能套用至計算欄位。在這種情況下，匯總是使用公式中匯總函式 (例如 AVG(Price)) 的直接結果。同樣地，您無法在此變更自動匯總，因為這會與 AVG 函式的輸出內容產生衝突。
[[["容易理解","easyToUnderstand","thumb-up"],["確實解決了我的問題","solvedMyProblem","thumb-up"],["其他","otherUp","thumb-up"]],[["難以理解","hardToUnderstand","thumb-down"],["資訊或程式碼範例有誤","incorrectInformationOrSampleCode","thumb-down"],["缺少我需要的資訊/範例","missingTheInformationSamplesINeed","thumb-down"],["翻譯問題","translationIssue","thumb-down"],["其他","otherDown","thumb-down"]],["上次更新時間：2025-07-31 (世界標準時間)。"],[],[],null,["# Aggregation is the process of **reducing** and **summarizing** tabular data. For example, consider the list of numbers following:\n\u003e 100, 200, 300, 400, 500\n\nUsing this example, you can state the following facts that illustrate the concept of aggregation:\n\nThere are other ways you can aggregate data, including calculating the median, count distinct, quartiles, percentiles, etc.\n\nDimensions and aggregation\n--------------------------\n\nThe previous example is based on a single set of numbers, but that's almost never what you see in the real world. In the real world, your data is typically organized into dimensions and metrics. Dimensions provide a way to categorize and group your data, while metrics measure that data.\n\nIn Looker Studio, aggregation **always** takes place in the context of a set of dimensions. That set of dimensions can be:\n\n- Every dimension, which lets you see the raw data.\n- A subset of your dimensions, which lets you see data broken down (grouped) by the dimensions you select.\n- The empty set, which lets you see a summary of the entire dataset.\n\nFor example, here are the same five numbers presented as daily stock prices. *Date* and *Ticker* are dimensions, *Price* is a metric.\n\nYou can now use the dimensions to group the data in different ways. For example:\n\n**By Ticker**\n\n**By Date**\n\nIn the examples above, the metric values depend on what you want to know about the data. For example, to calculate the average price for each company, apply the Average aggregation in conjunction with the *Ticker* dimension:\n\nTo see how many companies had stock information on a given day, you would use the *Date* dimension and the Count aggregation:\n\nNow, consider what happens when you use both the *Date* and *Ticker* dimensions in the stock table:\n\nWhen you create a group that includes all the available dimensions, the result is identical to the original data. **This is still an aggregation,** just not an interesting one, since every aggregation gives the same result. In Looker Studio, if you make a table and show every dimension, you're still able to set the aggregation type but it won't do anything.\n\nAggregation in Looker Studio\n----------------------------\n\nThere are several ways to apply an aggregation method to your data in Looker Studio:\n\n**In the data source.** A field's default aggregation determines how that metric is displayed in charts. See [Default aggregation](#default-aggregation) for more information.\n\n**In a chart** . Report editors can override the default aggregation and apply a different one to the metric on a chart by chart basis. Learn how to [add and edit data in charts](/looker/docs/studio/edit-fields-in-your-reports).\n\n**In a calculated field** . You can use specific aggregation functions within a calculated field formula to produce aggregated metrics. [See the list of functions](/looker/docs/studio/function-list).\n\n### Default aggregation\n\nYou can apply the following default aggregations to fields in data sources.\n\n#### **Change the aggregation method**\n\nTo change the field's aggregation method, edit the data source, then use the **Default aggregation** drop-down menu..\n\n### Auto aggregation\n\nSome data sources, such as Google Analytics and Google Ads, show Auto as the only available aggregation type for metrics. These data sets are already aggregated, reducing a potentially massive list of numbers to single values. The aggregations used can be simple, like sum or count, or more complex, like percentile. You can't change Auto aggregated metrics to a different aggregation type, since doing so would require Looker Studio to have access to the raw, unaggregated data.\n\nYou'll also see Auto aggregation applied to calculated fields based on other data sources, such as Sheets. In this case, the aggregation is a direct result of using an aggregation function in the formula, such as `AVG(Price)`. Again, you can't change the Auto aggregation here, because that would conflict with the output of the AVG function."]]
