Category: Clause

In this section, we are going to understand the working of the PostgreSQL FETCH clause, which is used to repond a portion of rows returned by a particular statement. The various RDBMS (relational database management systems) like H2, MySQL, and HSQLDB use the LIMIT clause extensively. And we have learnt Limit Clause in an earlier section of the PostgreSQL tutorial that it is used to constrain…

In this section, we are going to understand the working of the PostgreSQL LIMIT clause, which is used to get a subset of rows produced by a command. Syntax of PostgreSQL LIMIT Clause The basic syntax of the PostgreSQL LIMIT clause is as follows: In the above syntax, Limit clause returns row_count rows created by the command. And the offset…

In this section, we are going to understand the working of the PostgreSQL DISTINCT clause, which is used to delete the matching rows or data from a table and get only the unique records. Note: The DISTINCT clause is only used with the SELECT command.The DISTINCT clause can be useful to several columns in the select…

In this section, we are going to understand the working of the HAVING clause in PostgreSQL. The having clause is used to specify a search condition for a group or an aggregate. And it is regularly used with the GROUP BY clause to filter groups or aggregates based on a detailed condition. Syntax of PostgreSQL having clause…

In this section, we are going to understand the working of GROUP BY clause in PostgreSQL. We also see examples of how GROUP BY clause working with SUM() function, COUNT(), JOIN clause, multiple columns, and the without an aggregate function. The PostgreSQL GROUP BY condition is used with SELECT command, and it can also be used to reduce…

In this section, we are going to learn the PostgreSQL ORDER BY condition, which is used for sorting data in ascending or descending order. And the records are fetched on the basis of one or more columns. When fetching the records from a table, the SELECT command returns rows in an undetermined order. For this, we will…

In this section, we are going to understand the working of PostgreSQL where clause, which is used to filter the rows returned by a Select command. The WHERE condition is used to describe a condition while we get data from a table or a Join various tables. It is commonly used with SELECT, UPDATE, and DELETE commands to filter the…