count

问题 I have a problem, please see my database: ------------------- | id | article_id | ------------------- | 1 | 1 | | 2 | 1 | | 3 | 1 | | 4 | 2 | | 5 | 2 | | 6 | 3 | | 7 | 3 | | 8 | 3 | | 9 | 3 | | 10 | 3 | And I want to receive something like this (order by votes, from max to min): --------------------------- | id | article_id | votes | --------------------------- | 1 | 3 | 5 | | 2 | 1 | 3 | | 3 | 2 | 2 | Could you please help me to write proper sql query? 回答1: SELECT article_id, COUNT(article

问题 I would like to count all combinations in a data.frame. The data look like this 9 10 11 12 1 1 1 1 1 2 0 0 0 0 3 0 0 0 0 4 1 1 1 1 5 1 1 1 1 6 0 0 0 0 7 1 0 0 1 8 1 0 0 1 9 1 1 1 1 10 1 1 1 1 The output I want is simply comb n 1 1 1 1 5 0 0 0 0 3 1 0 0 1 2 Do you know any simple function to do that ? Thanks dt = structure(list(`9` = c(1, 0, 0, 1, 1, 0, 1, 1, 1, 1), `10` = c(1, 0, 0, 1, 1, 0, 0, 0, 1, 1), `11` = c(1, 0, 0, 1, 1, 0, 0, 0, 1, 1), `12` = c(1, 0, 0, 1, 1, 0, 1, 1, 1, 1)), .Names =

问题 I am trying to make a simple countRows function that will count the number of cells I have in a dynamic range. Basically if I have values in cells, say B2:B500, the count would return 499. However next time around values are in cell B2:B501, the count would return 500. But you wouldn't have to do anything to the cell in which you typed in the formula. I thought if I reference the cell as a Variant , then any value could be accepted. Then find the Address of that cell and return the Count of a

问题 select distinct "column" from table; output: column 1 0.0 2 [null] 3 1.0 But when I try to count the null values select count("column") from train where "column" is NULL; Gives output 0 (zero) Can you suggest where it's going wrong? 回答1: Use count(*) : select count(*) from train where "column" is NULL; count() with any other argument counts the non-NULL values, so there are none if "column" is NULL . 来源： https://stackoverflow.com/questions/53934294/how-to-count-null-values-in-postgresql

问题 Using PowerShell, I can import the CSV file and count how many objects are equal to "a". For example, @(Import-csv location | where-Object{$_.id -eq "a"}).Count Is there a way to go through every column and row looking for the same String "a" and adding onto count? Or do I have to do the same command over and over for every column, just with a different keyword? 回答1: Try cycling through properties like this: (Import-Csv location | %{$record = $_; $record | Get-Member -MemberType Properties |

问题 I would like to get the count of only items inside this file with sellingstatus->sellingstate of EndedWithSales ONLY, and perhaps also get the count for EnededWithoutSales . <sellingStatus> <currentPrice currencyId="USD">25.0</currentPrice> <convertedCurrentPrice currencyId="USD">25.0</convertedCurrentPrice> <bidCount>1</bidCount> <sellingState>EndedWithSales</sellingState> </sellingStatus> How would I go about passing this argument in php? Here is a link to the sample of XML: http:/

问题 I would like to get the count of only items inside this file with sellingstatus->sellingstate of EndedWithSales ONLY, and perhaps also get the count for EnededWithoutSales . <sellingStatus> <currentPrice currencyId="USD">25.0</currentPrice> <convertedCurrentPrice currencyId="USD">25.0</convertedCurrentPrice> <bidCount>1</bidCount> <sellingState>EndedWithSales</sellingState> </sellingStatus> How would I go about passing this argument in php? Here is a link to the sample of XML: http:/

问题 I would like to get the count of only items inside this file with sellingstatus->sellingstate of EndedWithSales ONLY, and perhaps also get the count for EnededWithoutSales . <sellingStatus> <currentPrice currencyId="USD">25.0</currentPrice> <convertedCurrentPrice currencyId="USD">25.0</convertedCurrentPrice> <bidCount>1</bidCount> <sellingState>EndedWithSales</sellingState> </sellingStatus> How would I go about passing this argument in php? Here is a link to the sample of XML: http:/

问题 I'm creating a new DataFrame with a handful of records from a Join. val joined_df = first_df.join(second_df, first_df.col("key") === second_df.col("key") && second_df.col("key").isNull, "left_outer") joined_df.repartition(1) joined_df.cache() joined_df.count() Everything is fast (under one second) except the count operation. The RDD conversion kicks in and literally takes hours to complete. Is there any way to speed things up? INFO MemoryStore: Block rdd_63_140 stored as values in memory

问题 I have this: $dbh = new PDO("odbc:Driver={Microsoft Access Driver (*.mdb, *.accdb)};Dbq=$mdbFilename", $username, $password); $sql = "SELECT * FROM this_table"; $stmt = $dbh->query($sql); //num of rows? How do I get the number of rows returned from that SELECT statement? Thanks all 回答1: SELECT count(*) FROM this_table is an option... Regarding rowCount: PDOStatement::rowCount() returns the number of rows affected by the last DELETE, INSERT, or UPDATE statement executed by the corresponding