Perform in postgresql

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Performing queries in PostgreSQL involves using the SELECT statement to retrieve data from tables in the database. The SELECT statement allows you to specify which columns to retrieve, define conditions with the WHERE clause, and sort the results with the ORDER BY clause.

Here is an example of a basic SELECT statement:

    SELECT column1, column2 FROM table_name;

In this example, “column1” and “column2” are the columns you want to retrieve from the “table_name” table.

To retrieve all columns from a table, you can use the “*” wildcard character:

    SELECT * FROM table_name;

You can also apply conditions to filter the results using the WHERE clause. For example:

    SELECT column1, column2 FROM table_name WHERE condition;

In this case, “condition” represents the criteria that the rows must meet. You can use logical operators such as “=” (equals), “<>” (not equals), “>” (greater than), “<” (less than), “>=” (greater than or equal to), and “<=” (less than or equal to) to define the condition.

To sort the results, you can use the ORDER BY clause, which specifies the column(s) to sort by:

    SELECT column1, column2 FROM table_name ORDER BY column1 ASC;

In this example, the query will retrieve the specified columns from the table and order the results by “column1” in ascending order (ASC).

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