In the following example we are retrieving all the values using the UNION ALL. Syntax of UNION ALL mysql> SELECT column_name FROM table_a We use the UNION ALL when we want to get all the values and not the distinct values. In the employeeaddress table we can see repetition of city name like Bangalore, Chennai and Kolkata, state name like KA, TN and WB.īut using the UNION in the query returns the city and state name only once as it is selecting only the unique i.e., distinct values. mysql>SELECT city, state, country FROM employeeaddress In the following example we are listing all the city, state and country name that are distinct in both the employeeadress and office tables. When using UNION in our query we will get distinct values from the tables. See the following sections covering the individual operators for more information and. When the ALL keyword follows a set operator, this causes duplicates to be included in the result. Each of these set operators supports an ALL modifier. | 6 | e05 | PRIMARY | Apartment 10 | Fast Food Block | Chennai | TN | INDIA | 600000 | MySQL has long supported UNION MySQL 8.0 adds support for INTERSECT and EXCEPT (MySQL 8.0.31 and later). | 5 | e04 | PRIMARY | Fruits Apartment | Fresh Block | Bangalore | KA | INDIA | 560000 | | 4 | e02 | PRIMARY | Pizza Street | Foodies Block | Kolkata | WB | INDIA | 700000 | | 3 | e03 | SECONDARY | House #301 ABC Colony | Jupiter Block | Kolkata | WB | INDIA | 700000 | | 2 | e03 | PRIMARY | Super Housing Complex Block 22 | Major Street | Chennai | TN | INDIA | 600000 | | 1 | e01 | PRIMARY | #12 street | Action block | Bangalore | KA | INDIA | 560000 | | id | employeeid | addresstype | addressline1 | addressline2 | city | state | country | pincode | Table: employeeaddress mysql> SELECT * FROM employeeaddress | o03 | Game | #12 Super Street | Master Block | Chennai | TN | INDIA | 600000 | | o02 | Apps | #321 Super Street | Action Road | Kolkata | WB | INDIA | 700000 | | o01 | Web Projects | #123 Awesome Street | Super Main | Bangalore | KA | INDIA | 560000 | | officeid | officename | addressline1 | addressline2 | city | state | country | pincode | Table: office mysql> SELECT * FROM office In this tutorial we will be using the office and employeeaddress table. Where, column_name must be of same type and same order in both the SELECT statements. Syntax of UNION mysql> SELECT column_name FROM table_a The data types of the columns in the SELECT query must also match.The columns in the SELECT query must also be in the same order.Each SELECT query must have the same number of columns when using UNION.We use the UNION operator when we want to combine the results of multiple SELECT query.įollowing are the points to note when using UNION in a query. (SELECT sscm_id FROM comment AS t2 WHERE t2.sscm_oid = 3ġ064 - You have an error in your SQL syntax check the manual that corresponds to your MySQL server version for the right syntax to use near 'UNION ALL (SELECT sscm_id FROM bpsocial_comment AS t2 WHERE t2.In this tutorial we will learn about union and union all in MySQL. (SELECT sscm_id FROM comment AS t1 WHERE t1.sscm_oid = 4 Some searching & googling seemed to suggest that placing () around each subquery might solve this problem but changing the query to SELECT * FROM comment AS tbl WHERE sscm_id IN SELECT sscm_id FROM comment AS t2 WHERE t2.sscm_oid = 3ġ221 - Incorrect usage of UNION and ORDER BY SELECT sscm_id FROM comment AS t1 WHERE t1.sscm_oid = 4 SELECT * FROM comment AS tbl WHERE sscm_id IN I have the following query which is intended to retrieve the newest 3 comments for each post in an array of posts.
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