I have two table, #1: row(int),id(int),type(int)
and next one #2: row(int),id(int),visit(int)
I want to set a query to select all of items in table #2 which has type=1 in table #1.
How to do that ?
Here you go :
SEELCT row, id, visit FROM table2 INNER JOIN table1 USING(id) WHERE table1.type = 1
Let me explain the
INNER JOIN table1 USING(id) :
JOIN means you collapse table rows of the table1 to the table2,
INNER excludes the rows where no id from the table1 match the id from the table2, and finally
USING(id) ask the engine to use the
id column to match rows.