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Copy Old Table to New Table within same Database in SQL.txt

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+// Copy Old Table to New Table within same Database.
+Within same Database 
+Syntax: CREATE TABLE new_table LIKE old_table;
+INSERT new_table SELECT * FROM old_table;
+ex: CREATE TABLE emp Like staff; INSERT emp SELECT * FROM staff;

Copy old Table to new Table different Database in SQL.txt

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+// Copy old Table to new Table
+Within different Database
+Use the database where you want to copy the old table
+syntax: CREATE TABLE new_table LIKE old_db.old_table;
+INSERT new_table SELECT * FROM old_db.old_table;
+
+ex: CREATE TABLE teacher LIKE my_db.student;
+INSERT teacher SELECT * FROM my_db.student;

Delete Records in Table in SQL.txt

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+// DELETE Records in Table
+The DELETE statement is used to delete records in a table.
+1. DELETE a specific Record
+Syntax: DELETE FROM table_name WHERE some_column = some_value;
+ex: DELETE FROM student_reg WHERE s_id = 105 AND name ='KAMAL';
+
+
+:-  select * from student_reg;
++------+---------+---------+------------+-----------+------+--------+-------+
+| s_id | name    | address | dob        | fees      | id   | result | marks |
++------+---------+---------+------------+-----------+------+--------+-------+
+|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | 1001 | SECOND |   300 |
+|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL | SECOND |   400 |
+|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL | FIRST  |   450 |
+|  104 | BIMAl   | KTM     | NULL       | 100200.00 | NULL | THIRD  |   250 |
+|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL | SECOND |   340 |
++------+---------+---------+------------+-----------+------+--------+-------+
+.Note :- WHERE is necessary otherqwise all records will be delete.
+2. DELETE ALL Records
+-> syntax: DELETE FROM table_name;
+OR//
+DELETE * FROM table_name;
+ex: DELETE FROM table_name;
+
+. Note : We cannot undo this
+

Drop Database using Drop Database in SQL.txt

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+Drop database.
+-> The DROP DATABSES statement is used to delete a database.
+syntax: DROP DATABSES database_name;
+ex: DROP DATABASE my_db;

Show Create Database in SQL.txt

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+// show create database
+It shows commands which you have written while creating your Database.
+syntax: SHOW CREATE DATABASE database_name;
+ex:SHOW CREATE DATABASE my_db;
+Output:
++----------+---------------------------------------------------------------------------------------------------------------------------------+
+| Database | Create Database
+                                                                 |
++----------+---------------------------------------------------------------------------------------------------------------------------------+
+| my_db    | CREATE DATABASE `my_db` /*!40100 DEFAULT CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci */ /*!80016 DEFAULT ENCRYPTION='N' */ |
++----------+---------------------------------------------------------------------------------------------------------------------------------+

Show Create Table in SQL.txt

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+Show Create Table
+-> It shows commands which you have written while creating your table.
+Syntax: SHOW CREATE TABLE table_name;
+ex:show create table student;
++---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+| Table   | Create Table
+
+                                                   |
++---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+
+| student | CREATE TABLE `student` (
+  `name` varchar(20) DEFAULT NULL,
+  `roll` int DEFAULT NULL,
+  `address` varchar(20) DEFAULT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci |
++---------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+

Show column in SQL.txt

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+// Show columns
+It shows all the columns of table and their data type along with any other columns
+specific details. it is just like DESC table_name.
+syntax: SHOW COLUMNS FROM table_name;
+ex: show columns from student;
++---------+-------------+------+-----+---------+-------+
+| Field   | Type        | Null | Key | Default | Extra |
++---------+-------------+------+-----+---------+-------+
+| name    | varchar(20) | YES  |     | NULL    |       |
+| roll    | int         | YES  |     | NULL    |       |
+| address | varchar(20) | YES  |     | NULL    |       |
++---------+-------------+------+-----+---------+-------+

Update Records in Table SQL.txt

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+// Update Records in Table.
+The Update statement is used existing records in a table.
+syntax: UPDATE table_name SET column1 = value1, column2=value2 WHERE some_column = some_value;
+ex:  UPDATE student_reg SET name ='RAM',fees=100000.23 WHERE s_id =101;
+mysql> select * from student_reg;
++------+---------+---------+------------+-----------+------+
+| s_id | name    | address | dob        | fees      | id   |
++------+---------+---------+------------+-----------+------+
+|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | NULL |
+|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL |
+|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL |
+|  104 | BIMAl   | KTM     | NULL       |   1001.23 | NULL |
+|  105 | KAMAL   | PKR     | 1956-12-12 | 100000.12 | NULL |
+|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL |
++------+---------+---------+------------+-----------+------+
+
+// example 2nd file data
+ex:UPDATE student_reg SET name ='RAM',id=1001 WHERE s_id =101;
+
+
+mysql> select * from student_reg;
++------+---------+---------+------------+-----------+------+
+| s_id | name    | address | dob        | fees      | id   |
++------+---------+---------+------------+-----------+------+
+|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | 1001 |
+|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL |
+|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL |
+|  104 | BIMAl   | KTM     | NULL       |   1001.23 | NULL |
+|  105 | KAMAL   | PKR     | 1956-12-12 | 100000.12 | NULL |
+|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL |
++------+---------+---------+------------+-----------+------+
+
+Ex:  UPDATE student_reg SET fees = 100200 WHERE s_id = 104;
+Output:select * from student_reg;
++------+---------+---------+------------+-----------+------+
+| s_id | name    | address | dob        | fees      | id   |
++------+---------+---------+------------+-----------+------+
+|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | 1001 |
+|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL |
+|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL |
+|  104 | BIMAl   | KTM     | NULL       | 100200.00 | NULL |
+|  105 | KAMAL   | PKR     | 1956-12-12 | 100000.12 | NULL |
+|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL |
++------+---------+---------+------------+-----------+------+
+
+
+
+Note: WHERE is necessary otherwise all records will be replace with given value.

Update with Case in SQL.txt

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+// Update with case
+synatx: UPDARE table_name SET new_column = CASE
+WHEN column_name1 = some_value1 THEN new_value1
+WHEN column_name2 = some_value2 THEN new_value2
+ELSE new_value3 END;
+ex: UPDATE student_reg SET result = CASE
+    -> WHEN marks >= 450 Then 'FIRST'
+    -> WHEN marks < 450 AND marks >=300 THEN 'SECOND'
+    -> WHEN marks < 300 AND marks >= 200 ThEN 'THIRD'
+    -> ELSE 'Fail' END;
+Query OK, 6 rows affected (0.01 sec)
+Rows matched: 6  Changed: 6  Warnings: 0
+
+mysql> select * from student_reg;
++------+---------+---------+------------+-----------+------+--------+-------+
+| s_id | name    | address | dob        | fees      | id   | result | marks |
++------+---------+---------+------------+-----------+------+--------+-------+
+|  101 | RAM     | KTM     | 1998-12-15 | 100000.23 | 1001 | SECOND |   300 |
+|  102 | SITA    | KTM     | 2001-10-11 | 200000.12 | NULL | SECOND |   400 |
+|  103 | HARI    | PKR     | 2001-01-12 |  10000.52 | NULL | FIRST  |   450 |
+|  104 | BIMAl   | KTM     | NULL       | 100200.00 | NULL | THIRD  |   250 |
+|  105 | KAMAL   | PKR     | 1956-12-12 | 100000.12 | NULL | Fail   |   150 |
+|  106 | SITA KC | PKR     | 1998-02-02 |  20000.12 | NULL | SECOND |   340 |
++------+---------+---------+------------+-----------+------+--------+-------+