Oracle Learning - 8

SQL: CREATE TableThe basic syntax for a CREATE TABLE is:CREATE TABLE table_name(column1 datatype null/not null,column2 datatype null/not null, ...);Each column must have a datatype. The column should either be defined as "null" or "not null" and if this value is left blank, the database assumes "null" as the default.For example:CREATE TABLE supplier ( supplier_id numeric(10) not null, supplier_name varchar2(50)...

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Oracle Learning - 7

SQL: INTERSECT QueryThe INTERSECT query allows you to return the results of 2 or more "select" queries. However, it only returns the rows selected by all queries. If a record exists in one query and not in the other, it will be omitted from the INTERSECT results.Each SQL statement within the INTERSECT query must have the same number of fields in the result sets with similar data types.The syntax for an INTERSECT query is:select...

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Oracle Learning - 6

SQL: UNION QueryThe UNION query allows you to combine the result sets of 2 or more "select" queries. It removes duplicate rows between the various "select" statements.Each SQL statement within the UNION query must have the same number of fields in the result sets with similar data types.The syntax for a UNION query is:select field1, field2, . field_nfrom tablesUNIONselect field1, field2, . field_nfrom tables;Example #1The following...

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Oracle Learning - 5

SQL: JoinsA join is used to combine rows from multiple tables. A join is performed whenever two or more tables is listed in the FROM clause of an SQL statement.There are different kinds of joins. Let's take a look at a few examples.Inner Join (simple join)Chances are, you've already written an SQL statement that uses an inner join. It is is the most common type of join. Inner joins return all rows from multiple tables where the...

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Oracle Learning - 4

SQL: GROUP BY ClauseThe GROUP BY clause can be used in a SELECT statement to collect data across multiple records and group the results by one or more columns.The syntax for the GROUP BY clause is:SELECT column1, column2, ... column_n, aggregate_function (expression)FROM tablesWHERE predicatesGROUP BY column1, column2, ... column_n;aggregate_function can be a function such as SUM, COUNT, MIN, or MAX.Example using the SUM functionFor...

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Oracle Learning - 3

SQL: BETWEEN ConditionThe BETWEEN condition allows you to retrieve values within a range.The syntax for the BETWEEN condition is:SELECT columnsFROM tablesWHERE column1 between value1 and value2;This SQL statement will return the records where column1 is within the range of value1 and value2 (inclusive). The BETWEEN function can be used in any valid SQL statement - select, insert, update, or delete.Example #1 - NumbersThe following...

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