How can I query two tables in the same database? For example, if the two tables are named "user" and "yong", how can I query the username and name fields of the table "user" and "yong" at the same time? How should I write SQL statements? Thank you for choosing SELECTcolumn_name (s) F. query the two tables in the same database
How can I query two tables in the same database? For example, if the two tables are named "user" and "yong", how can I query the username and name fields of the table "user" and "yong" at the same time? How should I write SQL statements? For more information, thank you.
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SELECT column_name (s) FROM table_name1
UNION ALL
SELECT column_name (s) FROM table_name2
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SQL code
SELECT u. username, y. name FROM user AS u, yong AS y;
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1. select a. *, B. * from a, B
2. select a. *, B. * from a left join B on a. a1 = B. b1
3. select a. * from a union all select B. * from B
What makes sense is 2; 1 and 3 depending on the on-site application needs
