modify sql code example

Example 1: sql change column types

ALTER TABLE table_name
ALTER COLUMN column_name datatype;

-- Example
ALTER TABLE product
ALTER COLUMN description VARCHAR(250);

Example 2: sql add column

ALTER TABLE Customers
ADD Email varchar(255);

Example 3: sql update query

--update query example
 UPDATE table_name
 SET column1 = value1, column2 = value2, ...
 WHERE condition;

Example 4: update column sql server

UPDATE table_name
SET column1 = value1, column2 = value2, ...
WHERE condition;

Example 5: alter table modify column

-- ORACLE 18c
ALTER TABLE table_name 
MODIFY column_name datatype;

-- Example
ALTER TABLE product
MODIFY description VARCHAR2(500 char);

Example 6: sql update from select

UPDATE YourTable 
SET Col1 = OtherTable.Col1, 
    Col2 = OtherTable.Col2 
FROM (
    SELECT ID, Col1, Col2 
    FROM other_table) AS OtherTable
WHERE 
    OtherTable.ID = YourTable.ID