MySQL insert into Statement Exercises: Insert a record into the table countries to ensure that, a country_id and region_id combination will be entered once in the table
MySQL insert into Statement: Exercise-9 with Solution
9. Write a SQL statement to insert a record into the table countries to ensure that, a country_id and region_id combination will be entered once in the table.
Create the table countries. CREATE TABLE IF NOT EXISTS countries ( COUNTRY_ID integer NOT NULL, COUNTRY_NAME varchar(40) NOT NULL, REGION_ID integer NOT NULL, PRIMARY KEY (COUNTRY_ID,REGION_ID) ); INSERT INTO countries VALUES(501,'India',185); mysql> SELECT * FROM countries; +------------+--------------+-----------+ | COUNTRY_ID | COUNTRY_NAME | REGION_ID | +------------+--------------+-----------+ | 501 | India | 185 | +------------+--------------+-----------+
Sample Solution:
INSERT INTO countries VALUES(501,'Italy',185);
Let execute the above code in MySQL 5.6 command prompt.
mysql> INSERT INTO countries VALUES(501,'Italy',185); ERROR 1062 (23000): Duplicate entry '501-185' for key 'PRIMARY'
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Previous:Write a SQL statement to insert one row in jobs table to ensure that no duplicate value will be entered in the job_id column.
Next:Write a SQL statement to insert rows into the table countries in which the value of country_id column will be unique and auto incremented.
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