![]() Subquery can be used in conjunction with the DELETE statement like with any other statements mentioned above.įollowing example deletes records from COMPANY table for all the customers whose AGE is greater than or equal to 27. This would impact two rows and finally COMPANY table would have the following records − WHERE AGE IN (SELECT AGE FROM COMPANY_BKP Either single or multiple columns in a table can be updated when using a subquery with the UPDATE statement.Īssuming, we have COMPANY_BKP table available which is a backup of COMPANY table.įollowing example updates SALARY by 0.50 times in COMPANY table for all the customers, whose AGE is greater than or equal to 27. The subquery can be used in conjunction with the UPDATE statement. JOIN, or INNER JOIN, is the most commonly used type of JOIN. To copy the complete COMPANY table into COMPANY_BKP, following is the syntax − JOIN is the same as INNER JOIN the INNER keyword is optional. innerjoin(x, y) : SELECT FROM x JOIN y ON x.a y.a leftjoin(x, y) : SELECT FROM x LEFT JOIN y ON x.a y.a rightjoin(x, y) : SELECT FROM x RIGHT. INSERT INTO table_name ) ]Ĭonsider a table COMPANY_BKP with similar structure as COMPANY table and can be created using the same CREATE TABLE using COMPANY_BKP as the table name. The Left Join or Left Outer Join operation takes two relations, A and B, and returns the inner join of A and B along with the unmatched rows of A. A self join uses the inner join or left join clause. The selected data in the subquery can be modified with any of the character, date, or number functions.įollowing is the basic syntax is as follows − INNER JOIN Syntax SELECT columnname (s) FROM table1 INNER JOIN table2 ON lumnname lumnname Demo Database In this tutorial we will use the well-known Northwind sample database. The INSERT statement uses the data returned from the subquery to insert into another table. You can use the self-join technique to find the employees located in the same city as the following query: SELECT DISTINCT e1.city, e1.firstName e1. The INNER JOIN keyword selects records that have matching values in both tables. Subqueries can also be used with INSERT statements. The unique columns for two tables are ID. Subqueries can be used with the SELECT, INSERT, UPDATE, and DELETE statements along with the operators such as =,, >=, SELECT * SELECT result FROM table1 LEFT OUTER JOIN table2 ON table1.keyfield1 table2.keyfield2 WHERE expr Pictorial Presentation Assume that, we have two tables table-A and table-B. A Subquery or Inner query or Nested query is a query within another SQLite query and embedded within the WHERE clause.Ī subquery is used to return data that will be used in the main query as a condition to further restrict the data to be retrieved.
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