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Seven examples of the uniq command: The uniq command in Linux can be used to process repeated lines in text files, this tutorial explains some of the most common usage of the uniq command, which may be helpful to you. The following file test will be used as a test file to explain how the uniq command works. $ Cat testaaaabbbbbbxx1. Syntax: $ uniq [-options] When the uniq command does not add any parameters, it will only remove
Seven examples of the uniq command: the uniq command in Linux can be used to process repeated lines in text files, this tutorial explains some of the most common usage of the uniq command, which may be helpful to you. The following File test will be used as the test file... seven examples of the uniq command: the uniq command in Linux can be used to process repeated lines in text files, this tutorial explains some of the most common usage of the uniq command, which may be helpful to you. The fol
Where a. Field 1 = B. Field 1 and A. Field 2 = B. Field 2 ) Casually speaking, the execution efficiency of the above statement is very low, you can consider the establishment of temporary tables, say need to judge the duplicate fields, rowID inserted in the temporary table, and then delete in the comparison. CREATE table temporary table as Select a. field 1,a. Field 2,max (A.rowid) dataid from official Table a GROUP by a. Field 1,a. field 2; Delete f
Tags: oid delete query drop person where copy Deb action methodThis article lists 3 ways to delete duplicate records, namely ROWID, group by and distinct, which can be consulted by small partners.For example, there is now a person table (table name: peosons)If you want to name, ID, address, the three fields exactly the same record queryThe code is as follows: Select p1.*From persons p1,persons P2where p1.idand P1.cardid = P2.cardid and P1.pname = p2.p
first to third path.#echo $PATH | Cut-d ': '-f 1-3/bin:/usr/bin:/sbin:Take the path variable out, I want to find the first to third, there is a fifth path.echo $PATH | Cut-d ': '-f 1-3,5/bin:/usr/bin:/sbin:/usr/local/binPractical Example: Display only/etc/passwd users and shells#cat/etc/passwd | Cut-d ': '-f 1,7 root:/bin/bashdaemon:/bin/shbin:/bin/shWCThe number of words in the statistics file, how many lines, how many characters.WC syntax[[email protected] ~]# WC [-LWM] options and Parameters
need to modify the source code. So in practice, this situation can set the combo box control's RowSourceType property value to "2-alias", and then the item that needs to be displayed in the combo box control from the table query out of the tables to generate a table or cursor, Dynamically assign a value to the RowSource property of the combo box control, so that you can solve the problem that you just mentioned. But there's a small problem here. The results of the "Department" field query for t
the raw data (the number of records remains unchanged ), • Grouping is used to aggregate statistics on raw data (with fewer records, one record is returned for each group ). Note: When rank () over (order by sort field order) is used for sorting, the null value is the largest. (If the sorting field is null, the null field may be placed at the top of the list during sorting, which affects the correctness of sorting. Therefore, we recommend that you change dense_rank () over (order by column name
Remove duplicate data on the basis of a large DataTable, create two small DataTable respectively, save multiple database connections, improve efficiency, speed up program running, datatable updates Database DataTable tab = new DataTable (); Tab = DBUtil. GetDataSet (strCmd, "TESTA. V_YHJ_VIP_WX_XSMX"). Tables [0]; Create a small table: DataView view = new DataView (tab );DataTable orderTable = view. ToTable
We can use the keyword distinct to remove duplicate elements in the result set, but this does not delete repeated elements in the database.If you want to delete data with repeated fields in a data table, it is a good way to use a temporary table as a transfer station.Suppose we want to delete extra rows of data with duplicate
Group group to remove duplicate data /*** Erase duplicate import data from the same topic* @author Tanteng* @date 2014.07.27*/Public Function fuck_repeat () {Set_time_limit (0);$sql = "Select" id ' from ' v95_special_content ' GROUP by ' specialid ', ' Curl ' has COUNT (' curl ') >1 ";$result = $this->db->query ($
records, only one record is retained, but it is often used to return the number of records that do not repeat, instead of returning all values of records that do not repeat. The reason is that distinct can only return its target field, but cannot return other fields. If distinct cannot solve the problem, I only use double loop query to solve the problem, this will undoubtedly directly affect the efficiency of a station with a large data volume.Let's take a look at the example below:The table st
PremiseWhen this article discusses only SQL Server queries,For non-composite statistics, where the statistics for each field contain only the data distribution of theHow to estimate the number of rows based on statistical information when combining queries with multiple fields.The algorithm principle of estimating the number of data rows using statistics from dif
Tags: mysql distinctAlthough distinct is a syntax for SQL and does not belong to MySQL, here is an example of MySQL.After so many years of distinct, incredibly has been wrong. Always thought that distinct is the removal of duplicate fields, originally it is to remove duplicate records.A repeating record is a record in
Remove duplicate data by day. If the value is 0, 0 is used. Otherwise, the maximum value is used. If the value is 0 Test data: mysql> select * from t2; + ---- + -------- + --------------------- + ---------- + | id | userid | inputDate | infoStatus | + ---- + -------- + --------------------- + ---------- + | 1 | 1 | 00:00:00 | 20013 | 2 | 1 | 00:00:00 | 0 | 3 | 2 | 00:00:11 | 20015 | 4 | 2 | 00:00:22 | 20013
the data that name does not repeat, then you must use distinct to remove the redundant duplicate records.select DISTINCT name from tableThe resulting results are:NameACIt seems to be working, but what I want to get is the ID value? Change the query statement:SELECT DISTINCT name, ID from tableThe result would be:ID Name1 A2 b3 C4 C5 bWhy doesn't distinct work? The role is actually up, but he also functions
Recently, a BUG occurred in the project. It took a long time to find the cause, which was caused by the previous "dirty" data. The specific "dirty" data is similar: Duplicate content is stored in some rows, such as 90133,90385and 9007,90071, 90072,90073, 90074,90075, 90076,9007. The correct content should be 90133, 9007,90071, 90072,90073, 90074,90075, 90076. The problem has been explained. What needs to be
Label:In MySQL to go heavy, is actually a very simple thing, to see the following example: mysql> DROP TABLE test; Query OK, 0 rows affected (0.01 sec) mysql> CREATE TABLE Test(ID INT,NAME VARCHAR (10));Query OK, 0 rows affected (0.01 sec) mysql> INSERT into Test VALUES (1, ' A1 '), (2, ' A2 '), (3, ' A3 '), (4, ' A4 '), (1, ' A1 ');Query OK, 5 rows Affected (0.0
"]. tostring () + "" + X ["name"]. tostring () + "" + X ["Address"]. tostring () ;}); console. writeline (); console. writeline ("-------------------- use LINQ to repeat the table --------------------"); VaR _ compresult = _ DT. asenumerable (). distinct (New datatablerowcompare (); datatable _ resultdt = _ compresult. copytodatatable (); _ resultdt. asenumerable (). tolist (). foreach (x => {console. writeline (X ["ID"]. tostring () + "" + X ["name"]. tostring () + "" + X ["Address"]. tostring
first field in B.txt, and if a[$1] has a value, the description also exists in the A.txt file, so that the data print out. Implementation Method 2: Copy Code code as follows: [Root@krlcgcms01 mytest]# awk-v ofs= "," ' nr==fnr{a[$1]=$2;} NR!=FNR $ in a {print $1,a[$1],$2,$3} ' a.txt b.txt 111,aaa,123,456 444,ddd,rts,786 Explanation:-v ofs= "," This is the column delimiter when the output is set, and in a This is the value of the first column in the B.txt file is not
Remove duplicate records from mongodb group query statistics The mongodb version is, MongoDB shell version: 2.4.4The operating environment and shell window are as follows: [mongo_user@mongodb_dbs ~]# mongo --port 30100MongoDB shell version: 2.4.4connecting to: 127.0.0.1:30000/testmongos> mongos> use posswitched to db posmongos> 1. count the number of group records first, and use the paymentOrder field to g
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