The first query we’re going to write is a simple query to verify whether duplicates do indeed exist in the table. For our example, my query looks like this: SELECT username, email,COUNT(*) FROM users GROUP BY username, email HAVINGCOUNT(*) >1 ...
We allot a unique row number to each record. The row_num column helps us identify the duplicates. Now we select the Name, Department, and Salary columns from the numbered_rows where the row number exceeds one. Why Duplicates in SQL Are Bad Duplicates in SQL tables are bad for various rea...
DISTINCT is used to remove duplicate rows from the SELECT query and only display one unique row from result set. Examples Let’s set up a new table in PostgreSQL and use it to look at a few helpful ways that DISTINCT can remove duplicates and reveal useful information from the data. First...
Every SQL query begins with aSELECTclause, leading some to refer to queries generally asSELECTstatements. After theSELECTkeyword comes a list of whatever columns you want returned in the result set. These columns are drawn from the table specified in theFROMclause. In SQL queries, the order of...
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In this article, we saw how to find duplicate values from a SQL table. First, we discussed how to use theCOUNTfunction. After that, we discussed how to useGROUP BYandHAVINGclauses. Next, we wrote the SQL query to find duplicates from the single column. ...
“conditions” names the conditions that must be met in order to select the records If you don’t want to remove duplicate data, or if you’re sure that there will be no duplicates in the result set, then you can use ALL instead of DISTINCT. But ALL is the default keyword in SQL st...
SELECTfruit_name, color,COUNT(*)FROMfruitsGROUPBYfruit_name, color;Code language:SQL (Structured Query Language)(sql) The query returned a single row for each combination of fruit name and color. It also included the rows without duplicates. ...
Let’s get the names of the countries without duplicates. Solution: We’ll use the keyword DISTINCT. Here’s the query: SELECT DISTINCT country FROM City; Here’s the result of the query: country Spain Poland Discussion: If you want the query to return only unique rows, use the keyword ...
Here are a few different ways you can use to manage duplicates using SQL. 1. Counting Duplicates Using Group by Function SQL is a multi-faceted programming language that offers various functions to simplify calculations. If you have plenty of experience with the aggregation functions in SQL, you...