select count distinct db2

Label:MySQL SQL statement, count this keyword can be in the number of statistics, such as There is a TableA table with the following data in the table: Id Name Age 1 Tony 18 2 Jacky 19 3 JoJo 18 SELECT COUNT (age) from TableA The above statement can

intoFooVALUES(4,'DEF Corp.','Joe','Client1'); INSERT intoFooVALUES(5,'DEF Corp.','Joe','Client3'); SELECT DISTINCTCompany , Sales_rep, client,MAX(RK1) Over(PARTITION bySALES_REP) asrep_distinct_client_cnt,MAX(RK2) Over(PARTITION byCompany ascompany_distinct_client_cnt from ( SELECTFookey, company, Sales_rep, Client, Dense_rank () Over(PARTITION bySales_repORDER byClient asRk1, Dense_rank () Over(PARTITION byCompanyORDER byClient asRK2 fromFoo) as

Hive count distinct, hivedistinct Select count (distinct user_id) from dm_user where ds = 20150701; With the disticnt function, all data is shuffled to only one CER, causing serious data skew of reducer. After optimization Set mapred. reduce. tasks = 50;

Mysql queries non-duplicated row content and the number of non-Repeated Records count. distinct has such a table that records id, p_id, p_name, p_content, p_time 1 343 aaa aaaaaa 2012-09-01 2 344 bbb bbbbbb 2012-09-02 3 321 ccc cccccccc 2012-09-03 www.2cto.com 4 343 aaa aaaaaa 2012-09-04 want to query the content of non-repeated rows, and output p_sum (number of product p_id repetitions)

the mysql Manual. I realized what I needed with group_concat (distinct name) and group by name, try it now. Error ............ Depressed ....... I can't even go through the mysql Manual. I gave me hope first, and then pushed me to disappointment .... Check again. The group_concat function is supported by 4.1, dizzy. I have 4.0. No way. Upgrade. the upgrade is successful ...... Finally, the customer must be asked to upgrade. Suddenly, the ghost machin

reported, depressing!I can't even go through the mysql Manual. I gave me hope first, and then pushed me down.Check again. The group_concat function is supported by 4.1, dizzy. I have 4.0. No way. Upgrade. the upgrade is successful.Finally, the customer must be asked to upgrade.Suddenly, the ghost machine flashed. since the group_concat function can be used, can other functions be used?Hurry and use the count function for a try. it's as easy as it tak

usage in the MySQL manual. I realized what I needed with group_concat (distinct name) and group by name, try it now. Error ............ Depressed ....... I can't even go through the MySQL manual. I gave me hope first, and then pushed me to disappointment .... Check again. The group_concat function is supported by 4.1, dizzy. I have 4.0. No way. Upgrade. The upgrade is successful ...... Finally, the customer must be asked to upgrade. Suddenly,

a test, success.Finally, but then, you have to ask customers to upgrade.Suddenly the spirit flashes, and since you can use the Group_concat function, can the other functions be OK?Hurriedly with the Count function a try, success, cost so much effort, originally so simple.Now release the full statement:SELECT *, COUNT (distinct name) from the table group by nameR

, must have the same ID and test1 will be excluded, this is not possible, the ID is automatically increased ...Let's change the query statement:Select ID, distinct test1 from testUnfortunately, in addition to the error message you get nothing, distinct must be placed at the beginning. Is it difficult to put distinct in a where condition? Can, still error ....The

手册里找到一个用法，用group_concat(distinct name)配合group by name实现了我所需要的功能，兴奋，天佑我也，赶快试试。报错。。。。。。。。。。。。郁闷。。。。。。。连mysql手册也跟我过不去，先给了我希望，然后又把我推向失望，好狠哪。。。。再仔细一查，group_concat函数是4.1支持，晕，我4.0的。没办法，升级，升完级一试，成功。。。。。。终于搞定了，不过这样一来，又必须要求客户也升级了。突然灵机一闪，既然可以使用group_concat函数，那其它函数能行吗？赶紧用count函数一试，成功，我。。。。。。。想哭啊，费了这么多工夫。。。。。。。。原来就这么简单。。。。。。 现在将完整语句放出:select *,

How to use SQL select distinct, selectdistinct Duplicate values may exist in the table. This is not a problem. However, sometimes you may want to list only different values. The keyword distinct is used to return a unique value. Table: Example 1 Copy codeThe Code is as follows:Select distinct name from The resul

ArticleDirectory Syntax: "Orders" table: Result: Result: SQL select distinct statement Duplicate values may exist in the table. This is not a problem. However, sometimes you may want to list only different values. The keyword distinct is used to return a unique value. Syntax: Select

Label:In the table, duplicate values may be included. That's not a problem, but sometimes you might want to just list different values (distinct). Keyword DISTINCT is used to return only different values.Grammar:SELECT DISTINCT column name from table nameUsing DISTINCT KeywordsIf you want to pick all the values from th

, must be the same ID and test1 will be excluded. It's impossible. ID is self-growing.。。Let's change the query statement:Select ID, distinct test1 from testVery sorry. You can't get anything but the wrong information. Distinct must be placed at the beginning.Is it difficult to put distinct in a where condition? Yes. Still error ...。。。。By reviewing the manual. Can

In a table, you might include duplicate values. This is not a problem, but sometimes you may want to list only the different values (distinct). Keyword DISTINCT is used to return only a different value. Table A: Example 1 Copy Code code as follows: Select distinct name from A The results of the im

In DB2, the sum function used to replace the count query is to calculate and sum the column values. The www.2cto.com count function accumulates the columns that meet the conditions and adds one when the conditions are met. The count function is commonly used to count the num

Label:SQL Server Databasethe Count () function returns the number of rows that match the specified criteria. The syntax SQL count (column_name) syntax count (column_name) function returns the number of values for the specified column (NULL does not count in): SELECT

(*) from TableName; This optimization applies only to MyISAM tables, because these table types store the exact number of records returned by a function and are very easy to access. For transactional storage engines (InnoDB, BDB), the problem of storing an exact number of rows is more, because multiple-thing processing can occur, each of which can have an impact on the number of rows.COUNT (DISTINCT expr,[expr ...])Returns the number of

TableName; This optimization applies only to MyISAM tables, because these table types store the exact number of records returned by a function and are very easy to access. For transactional storage engines (InnoDB, BDB), the problem of storing an exact number of rows is more, because multiple-thing processing can occur, each of which can have an impact on the number of rows.COUNT (DISTINCT expr,[expr ...])Returns the number of

access. For a transaction-type storage engine (InnoDB, BDB), there are more problems storing an exact number of rows, because multiple things can happen, and each can have an impact on the number of rows. COUNT (DISTINCT expr,[expr ...]) Returns the number of different non-null values. If no matching items are found, COUNT (