Writing SQL Statements

Writing SQL Statements :

• SQL statements are not case-sensitive
• SQL statements can be on one or more lines
• Keywords cannot be abbreviated or split across lines
• Clauses are usually placed on separate lines
• Indents are used to enhance readability
• In SQL Query Tool(PGADMIN3), SQL statements can optionally be terminated by a semicolon (;)
• Semicolons are required if you execute multiple SQL statements
• In PSQL Client, you are required to end each SQL statement with a semicolon (;)

SQL SELECT Statement

Capabilities of SQL SELECT Statements :



Basic SELECT Statement :

• SELECT * | {[DISTINCT] column | expression [alias],...} FROM table;
• SELECT identifies the columns to be displayed
• FROM identifies the table containing those columns
• * specifies Selecting All Columns
• column name specifies : selecting Specific Columns
• eg1 : postgres=# select*from dept; (will return the all the columns of table dept)
  
• eg2 : edb=# select deptno, dname from dept; (will return the specific columns of table dept)