PostgreSQL中的LEFT JOIN(左连接)是一种常用的SQL连接类型,它返回左表(即连接语句中位于LEFT JOIN关键字之前的表)的所有记录,以及右表中与左表匹配的记录。如果右表中没有匹配...
INNER JOIN 与 OUTER JOIN 内连接在JOIN表中查找公共元组,外连接始终获取一侧的所有数据并在另一侧找相应的匹配项: postgres=# select * from t10 left join t11 on t10.id1=t11.id1;id1|id2|id1|id2 ---+---+---+---1|2||2|3|2|43|4|3|5(3行记录) 1. 2. 3. 4. 5. 6. 7. ...
SELECT[左表字段],[右表字段]FROMleft_tableLEFTJOINright_tableONleft_table.key=right_table.key 1. 2. 3. 4. 5. 6. 2.2 与 INNER JOIN 的差异对比 -- INNER JOIN结果(仅匹配记录)SELECT,sp.product_idFROMsuppliers sINNERJOINsupplier_products spONs.supplier_id=sp.supplier_id;-- LEFT JOIN结果(保...
PostgreSQL中的UPDATE LEFT JOIN操作允许你在更新表时使用左连接(LEFT JOIN)来关联另一个表的数据。以下是关于这个操作的基础概念、优势、类型、应用场景以及可能遇到的问题和解决方法。 基础概念 LEFT JOIN:返回左表中的所有记录,以及右表中匹配的记录。如果右表中没有匹配的记录,则结果是NULL。 UPDATE LEFT JOIN:...
40TPT.INSERT_OPER41from T_BUDGET_DETAIL tbd join T_BUDGET_ITEM tbi on tbd.item_id =tbi.item_id42left join T_BUDGET tb on tb.budget_id =tbi.budget_id43LEFT JOIN T_PROJECT_TRACE TPT ON TPT.BUDGET_DETAIL_ID =tbd.BUDGET_DETAIL_ID44left join t_organization tot on tbd.org_code =tot...
LEFTJOIN t_right r ONr.value = l.value WHEREr.valueISNULL; 1 2 3 4 5 6 7 SELECTl.* FROMt_left l WHEREl.valueNOTIN ( SELECTvalue FROMt_right r ); 1 2 3 4 5 6 7 8 SELECTl.* FROMt_left l WHERENOTEXISTS ( SELECTNULL ...
left outer join pg_stat_activity a2 -- select * from pg_stat_activity on a0.id = a2.pid order by '/'||array_to_string(a0.pathid,'/'),a0.depth; 输出结果格式如下: 附录三:查询当前执行时间超过60s的sql select pg_stat_activity.datname, ...
PostgreSQL left join问题0 悬赏园豆:200 [待解决问题] 浏览: 1039次 SELECT field_abcd AS field_abcd FROM ( (SELECT ad.oi AS oioi, ad.ad AS adad FROM dd LEFT JOIN da ON (da.dac = dd.dac AND da.ti = '111') LEFT JOIN ad ON (dd.oi = ad.oi AND ad.ti = '111' AND ad.odan...
CREATE OPERATOR name ( PROCEDURE = func_name [, LEFTARG = left_type ] [, RIGHTARG = right_type ] [, COMMUTATOR = com_op ] [, NEGATOR = neg_op ] [, RESTRICT = res_proc ] [, JOIN = join_proc ] [, HASHES ] [, MERGES ] [, SORT1 = left_sort_op ] [, SORT2 = right_...