數據源：
“姓名”“基數”“個人比例”“個人繳納”“公司比例”“公司繳納”“總計”，共7列7行數據，其中姓名列，第1、2行與第6、7行內容重復
目標：
留下第1、2、6、7姓名列中內容重復的行
操作過程：
選取指定列》【主頁】》【保留行】》【保留重復項】
M公式：
= let columnNames = {"指定列名"}, addCount = Table.Group(步驟名, columnNames, {{"Count", Table.RowCount, type number}}), selectDuplicates = Table.SelectRows(addCount, each [Count] > 1), removeCount = Table.RemoveColumns(selectDuplicates, "Count") in Table.Join(步驟名, columnNames, removeCount, columnNames, JoinKind.Inner)
說明：
= let columnNames = {"指定列名"}, addCount = Table.Group(步驟名, columnNames, {{"Count", Table.RowCount, type number}}), selectDuplicates = Table.SelectRows(addCount, each [Count] > 1), removeCount = Table.RemoveColumns(selectDuplicates, "Count") in Table.Join(步驟名, columnNames, removeCount, columnNames, JoinKind.Inner)
- 給指定的列名一個說法，叫作“columnNames”
= let columnNames = {"指定列名"}, addCount = Table.Group(步驟名, columnNames, {{"Count", Table.RowCount, type number}}), selectDuplicates = Table.SelectRows(addCount, each [Count] > 1), removeCount = Table.RemoveColumns(selectDuplicates, "Count") in Table.Join(步驟名, columnNames, removeCount, columnNames, JoinKind.Inner)
- 【分組依據】計算指定列里各個值出現次數，並將這結果命名為addCount
= let columnNames = {"指定列名"}, addCount = Table.Group(步驟名, columnNames, {{"Count", Table.RowCount, type number}}), selectDuplicates = Table.SelectRows(addCount, each [Count] > 1), removeCount = Table.RemoveColumns(selectDuplicates, "Count") in Table.Join(步驟名, columnNames, removeCount, columnNames, JoinKind.Inner)
- 【保留行】保留“Count”列中值大於1的行
= let columnNames = {"指定列名"}, addCount = Table.Group(步驟名, columnNames, {{"Count", Table.RowCount, type number}}), selectDuplicates = Table.SelectRows(addCount, each [Count] > 1), removeCount = Table.RemoveColumns(selectDuplicates, "Count") in Table.Join(步驟名, columnNames, removeCount, columnNames, JoinKind.Inner)
- 【刪除列】將“Count”列刪除
= let columnNames = {"指定列名"}, addCount = Table.Group(步驟名, columnNames, {{"Count", Table.RowCount, type number}}), selectDuplicates = Table.SelectRows(addCount, each [Count] > 1), removeCount = Table.RemoveColumns(selectDuplicates, "Count") in Table.Join(步驟名, columnNames, removeCount, columnNames, JoinKind.Inner)
- 將原表和只保留重復值的表進行【合並查詢】，連接種類使用“內部”
將所有步驟拆分如圖所示。
其中核心部分：
addCount = Table.Group( 更改的類型,"姓名", {{"Count", Table.RowCount, type number}}),
selectDuplicates = Table.SelectRows(addCount, each [Count] > 1),
removeCount = Table.RemoveColumns(selectDuplicates, "Count"),
最后一步 = Table.Join(更改的類型, "姓名", removeCount, "姓名", JoinKind.Inner)
最終效果：
數據只剩下姓名列中重復的四行數據
多說一句：
好吧，我承認，我被這個公式驚到了！這其實已經不是一個簡單的公式，而是一段M代碼，這不是有let開頭，in結尾么……