SQL SELECT Statement: The most commonly used SQL command is SELECT statement. The SQL SELECT statement is used to query or retrieve data from a table in the database. A query may retrieve information from specified columns or from all of the columns in the table. To create a simple SQL SELECT Statement, you must specify the column(s) name and the table name. The whole query is called SQL SELECT Statement.... Syntax of SQL SELECT Statement: SELECT column_list FROM table-name [WHERE Clause] [GROUP BY clause] [HAVING clause] [ORDER BY clause]; • table-name is the name of the table from which the information is retrieved. • column_list includes one or more columns from which data is retrieved. • The code within the brackets is optional. database table student_details; Id first_name last_name age Subject games 100 Rahul Sharma 10 Science Cricket 101 Anjali Bhagwat 12 Maths Football 102 Stephen Fleming 09 Science Cricket 103 Shekar Gowda 18 Maths Badminton 104 Priya Chandra 15 Economics Chess NOTE: These database tables are used here for better explanation of SQL commands. In reality, the tables can have different columns and different data. For example, consider the table student_details. To select the first name of all the students the query would be like: SELECT first_name FROM student_details; NOTE: The commands are not case sensitive. The above SELECT statement can also be written as "select first_name from students_details;" We can also retrieve data from more than one column. For example, to select first name and last name of all the students. SELECT first_name, last_name FROM student_details; We can also use clauses like WHERE, GROUP BY, HAVING, ORDER BY with SELECT statement. NOTE: In a SQL SELECT statement only SELECT and FROM statements are mandatory. Other clauses like WHERE, ORDER BY, GROUP BY, HAVING are optional.
Posted on: Sat, 10 Aug 2013 02:47:48 +0000
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