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Tag Archives: SQL

Where Clause – SQL

Where Clause – SQL is used to specify a condition while fetching the data from single table or joining with multiple tables. If the given condition is satisfied then only it returns specific value from the table. You would use WHERE clause to filter the records and fetching only necessary records. The WHERE clause is not only used in SELECT ...

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ALTER TABLE Command – SQL

ALTER TABLE Command – SQL is used to add, delete or modify columns in an existing table. You would also use ALTER TABLE command to add and drop various constraints on a an existing table. Syntax: The basic syntax of ALTER TABLE to add a new column in an existing table is as follows: ALTER TABLE table_name ADD column_name datatype; ...

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MIN Function SQL

MIN Function SQL is used to find out the record with minimum value among a record set. To understand MIN function, consider an employee_tbl table, which is having the following records: SQL> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram ...

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AND and OR Conjunctive Operators – SQL

AND and OR Conjunctive Operators – SQL are used to combine multiple conditions to narrow data in an SQL statement. These two operators are called conjunctive operators. These operators provide a means to make multiple comparisons with different operators in the same SQL statement. The AND Operator: The AND operator allows the existence of multiple conditions in an SQL statement’s ...

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TRUNCATE TABLE Command – SQL

TRUNCATE TABLE Command – SQL – is used to delete complete data from an existing table. You can also use DROP TABLE command to delete complete table but it would remove complete table structure form the database and you would need to re-create this table once again if you wish you store some data. Syntax: The basic syntax of TRUNCATE ...

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AVG Function SQL

AVG Function SQL is used to find out the average of a field in various records. To understand AVG function, consider an employee_tbl table, which is having the following records: SQL> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram | ...

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Overview – SQL

Overview – SQL tutorial gives unique learning on Structured Query Language and it helps to make practice on SQL commands which provides immediate results. SQL is a language of database, it includes database creation, deletion, fetching rows and modifying rows etc. SQL is an ANSI (American National Standards Institute) standard but there are many different versions of the SQL language. ...

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Update Query – SQL

Update Query – SQL is used to modify the existing records in a table. You can use WHERE clause with UPDATE query to update selected rows otherwise all the rows would be affected. Syntax: The basic syntax of UPDATE query with WHERE clause is as follows: UPDATE table_name SET column1 = value1, column2 = value2...., columnN = valueN WHERE [condition]; ...

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Using Views – SQL

Using Views – SQL –  is nothing more than a SQL statement that is stored in the database with an associated name. A view is actually a composition of a table in the form of a predefined SQL query. A view can contain all rows of a table or select rows from a table. A view can be created from ...

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SUM Function SQL

SUM Function SQL is used to find out the sum of a field in various records. To understand SUM function, consider an employee_tbl table, which is having the following records: SQL> SELECT * FROM employee_tbl; +------+------+------------+--------------------+ | id | name | work_date | daily_typing_pages | +------+------+------------+--------------------+ | 1 | John | 2007-01-24 | 250 | | 2 | Ram | ...

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