从多个表中选择行

Question

I am trying to get data from multiple tables (all tables are identical)

Select column1,column2 From table1,table2

Is it a correct way to get this in MYSQL. (I am passing table names dynamically in the query)

Answer 1

The syntax you need is this one :

SELECT a.column1, b.column2
FROM table1 AS a, table2 AS b

AS give your table an alias you can directly use in your request.

Answer 2

Like:

SELECT table1.column1, table2.column2 
FROM table1, table2

By fully-qualifying the column using the table, you won't run into conflicts when columns have the same names in the tables. As zessx states in his answer, an alternate way to do this is to alias the tables, which can make the query simpler with long table names / schema names.

Answer 3

Maybe this:

 SELECT column1, column2
 FROM table1
 UNION ALL
 SELECT column1, column2
 FROM table2

But you cannot pass in table names dynamically. They must be known to the database in advance (so you need to construct the SQL in your program first).