SQL(postgresql?
What is the left and right table for joins after the first join in SQL(postgresql?
我想知道,第一次join后左table和右table是什么组成
例如:
From final_productions fp
left join things.pc p on fp.production_id = p.id
left join events.time t on fp.tx_id = t.id
left join things.car c on c.id = fp.channel_id
right join events.form f on f.production_id = p.id
left join events.trigger_alert ta on mc.cue_sheet_id = ta.id
我知道第一个左连接 inner join things.pc p on fp.production_id = p.id
左 table 将是 from statement
中的 table,即 final_productions
。但是其他连接(即第一个连接语句之后的连接)呢?有人可以解释一下吗?谢谢
Parentheses can be used around JOIN
clauses to control the join order. In the absence of parentheses, JOIN clauses nest left-to-right.
所以
a LEFT JOIN b RIGHT JOIN c
与
相同
(a LEFT JOIN b) RIGHT JOIN c
我想知道,第一次join后左table和右table是什么组成
例如:
From final_productions fp
left join things.pc p on fp.production_id = p.id
left join events.time t on fp.tx_id = t.id
left join things.car c on c.id = fp.channel_id
right join events.form f on f.production_id = p.id
left join events.trigger_alert ta on mc.cue_sheet_id = ta.id
我知道第一个左连接 inner join things.pc p on fp.production_id = p.id
左 table 将是 from statement
中的 table,即 final_productions
。但是其他连接(即第一个连接语句之后的连接)呢?有人可以解释一下吗?谢谢
Parentheses can be used around
JOIN
clauses to control the join order. In the absence of parentheses, JOIN clauses nest left-to-right.
所以
a LEFT JOIN b RIGHT JOIN c
与
相同(a LEFT JOIN b) RIGHT JOIN c