SQL UPDATE Statement Updating Data in a Table. Summary in this tutorial, you will learn how to use SQL UPDATE statement to modify existing data in a table. SQL UPDATE syntax. The UPDATE statement changes existing data in one or more rows in a table. The following illustrates the syntax of the UPDATE statement To update data in a table, you need to First, specify the table name that you want to change data in the UPDATE clause. Second, assign a new value for the column that you want to update. In case you want to update data in multiple columns, each column value pair is separated by a comma ,. Third, specify which rows you want to update in the WHERE clause. The WHERE clause is optional. If you omit the WHERE clause, all rows in the table will be updated. The database engine issues a message specifying the number of affected rows after you execute the statement. SQL UPDATE statement examples. Lets take a look at some examples of using UPDATE statement with the employees table SQL UPDATE one column example. Suppose Janet, who has employee id 3, gets married so that you need to change her last name in the employees table. The record of Janet in the employees before update is as follows employeeid,lastname,firstname. The following statement changes Janets last name from Levering to Hill Execute the SELECT statement above again to verify the change SQL UPDATE multiple columns example. For example, Janet moved to a new house therefore her address changed. Now, you have to change it in the employees table by using the following statement address1. Carter St,SQL UPDATE multiple rows example. The following UPDATE statement increases the salary by 2 for employees whose salary is less than 2. Thee employees whose salary is less than 2. K received the promotion. SQL UPDATE from SELECTThe following query selects sales person who has was in charge of more than 1. COUNTorderidHAVINGCOUNTorderid 1. The following query increases salary of the best sale persons by 5. The best sale person ids are provided by a subquery. employeeid,COUNTorderid HAVINGCOUNTorderid 1. In this tutorial, we have shown you how to use the SQL UPDATE statement to change data in one or more rows in a table. In this tutorial, you will learn how to use SQL UPDATE statement to change existing data in a table. This SQL tutorial explains how to use the SQL UPDATE statement with syntax, examples and practice exercises. Notice that there are 3 ways to write a SQL UPDATE statement. I am wondering if this is possible at all. I want to update column x if a condition is true, otherwise column y would be updated UPDATE table SET CASE CONDITION.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
November 2017
Categories |