PostgreSQL – GROUP BY The PostgreSQL GROUP BY clause is used in collaboration with the SELECT statement to group together those rows in a table that have identical data. This is done to eliminate redundancy in the output and/or compute aggregates that apply to these groups. The GROUP BY clause follows the WHERE clause in a …
PostgreSQL – ORDER BY Clause The PostgreSQL ORDER BY clause is used to sort the data in ascending or descending order, based on one or more columns. Syntax The basic syntax of ORDER BY clause is as follows − SELECT column-list FROM table_name [WHERE condition] [ORDER BY column1, column2, .. columnN] [ASC | DESC]; You can …
PostgreSQL – LIMIT Clause The PostgreSQL LIMIT clause is used to limit the data amount returned by the SELECT statement. Syntax The basic syntax of SELECT statement with LIMIT clause is as follows − SELECT column1, column2, columnN FROM table_name LIMIT [no of rows] The following is the syntax of LIMIT clause when it is used …
PostgreSQL – LIKE Clause The PostgreSQL LIKE operator is used to match text values against a pattern using wildcards. If the search expression can be matched to the pattern expression, the LIKE operator will return true, which is 1. There are two wildcards used in conjunction with the LIKE operator − The percent sign (%) The underscore …
PostgreSQL – DELETE Query The PostgreSQL DELETE Query is used to delete the existing records from a table. You can use WHERE clause with DELETE query to delete the selected rows. Otherwise, all the records would be deleted. Syntax The basic syntax of DELETE query with WHERE clause is as follows − DELETE FROM table_name WHERE …
PostgreSQL – UPDATE Query The PostgreSQL UPDATE Query is used to modify the existing records in a table. You can use WHERE clause with UPDATE query to update the selected rows. Otherwise, all the rows would be updated. Syntax The basic syntax of UPDATE query with WHERE clause is as follows − UPDATE table_name SET column1 …
AND and OR Conjunctive Operators The PostgreSQL AND and OR operators are used to combine multiple conditions to narrow down selected data in a PostgreSQL statement. These two operators are called conjunctive operators. These operators provide a means to make multiple comparisons with different operators in the same PostgreSQL statement. The AND Operator The AND operator allows the existence of …
PostgreSQL – WHERE Clause The PostgreSQL WHERE clause is used to specify a condition while fetching the data from single table or joining with multiple tables. If the given condition is satisfied, only then it returns specific value from the table. You can filter out rows that you do not want included in the …
PostgreSQL – Expressions An expression is a combination of one or more values, operators, and PostgresSQL functions that evaluate to a value. PostgreSQL EXPRESSIONS are like formulas and they are written in query language. You can also use to query the database for specific set of data. Syntax Consider the basic syntax of the …
PostgreSQL – Operators What is an Operator in PostgreSQL? An operator is a reserved word or a character used primarily in a PostgreSQL statement’s WHERE clause to perform operation(s), such as comparisons and arithmetic operations. Operators are used to specify conditions in a PostgreSQL statement and to serve as conjunctions for multiple conditions in …