The DISTINCT clause is used in a SELECT statement to eliminate duplicate rows from the result set. It ensures that only unique values are returned for the specified columns, effectively reducing the result set to distinct rows. The basic syntax of using the DISTINCT clause is as follows: SELECT DISTINCT column1, column2, … FROM table_name…
The ORDER BY clause is used in a SELECT statement to sort the result set based on one or more columns. It allows you to specify the sorting order for the returned rows, which can be either ascending (ASC) or descending (DESC). The basic syntax of the ORDER BY clause is as follows: SELECT column1,…
The SELECT statement is a fundamental SQL statement used in PostgreSQL (and other relational database systems) to retrieve data from a database table. It allows you to query and retrieve specific columns and rows of data based on your criteria. The basic syntax of a SELECT statement in PostgreSQL is as follows: SELECT column1, column2,…
The REGEXP_MATCHES function is used to perform regular expression pattern matching on a given string. It returns all substrings in the input string that match a specified regular expression pattern. This function is useful when you need to extract specific pieces of information from a text based on a pattern. The syntax of the REGEXP_MATCHES…
The REGEXP_REPLACE function is used to replace substrings within a string based on a regular expression pattern. It allows you to perform advanced pattern-based replacements on text data. The syntax of the REGEXP_REPLACE function is as follows: REGEXP_REPLACE(string, pattern, replacement, flags) where string is the input string in which you want to perform replacements. and…
The MD5 function is used to calculate the MD5 hash value of a given input string. MD5 (Message Digest Algorithm 5) is a widely used cryptographic hash function that produces a fixed-size 128-bit (16-byte) hash value, typically represented as a 32-character hexadecimal number. The syntax of the MD5 function is as follows: MD5(string) where string…
The ASCII function is used to return the ASCII code value of the first character in a given string. The ASCII code is a numerical representation of a character in the ASCII character set. The syntax of the ASCII function is as follows: ASCII(string) and string is the input string for which you want to…
The CHR function is used to return the character corresponding to a specified ASCII code or Unicode code point. It’s a convenient way to generate characters based on their numeric representations. The syntax of the CHR function is as follows: CHR(code) where code is the numeric code that represents the character you want to retrieve….
The LPAD function is used to pad a string on the left side with a specified character or a repeated sequence of characters, until the resulting string reaches a specified length. This function is often used to align strings to a specific width. The syntax of the LPAD function is as follows: LPAD(string, length, fill_character)…
The FORMAT function is used to format a string using placeholders that are replaced with corresponding values. It’s a powerful function that allows you to create formatted strings with specific patterns and insert values into those patterns. The syntax of the FORMAT function is as follows: FORMAT(format_string, value1, value2, …) where format_string is the string…