Deleting duplicate rows from a table is a little bit tricky. Finding and deleting duplicate rows is pretty easy if the table has a limited number of records. However, if the table has enormous data, then finding and deleting the duplicates can be challenging. PostgreSQL provides multiple ways ...
Merge Join (cost=1.47..47922.57 rows=99040 width=93) Merge Cond: (a.id = b.id) -> Index Scan using idx_testtab01_id on testtab01 a (cost=0.43..413538.43 rows=10000000 width=89) -> Index Only Scan using idx_testtab02_id on testtab02 b (cost=0.42..4047.63 rows=99040 width=4)...
mydb=>CREATETABLEtbl_batch3(id int4,info text);CREATETABLEmydb=>INSERTINTOtbl_batch3(id,info)VALUES(1,'a'),(2,'b'),(3,'c');INSERT0 3 1. 2. 3. 4. 5. 数据如下: 复制 mydb=>SELECT*FROMtbl_batch3;id | info---+---1 | a2 | b3 | c(3rows) 1. 2. 3. 4. 5. 6....
mydb=>CREATETABLEtbl_batch3(idint4,infotext);CREATETABLEmydb=>INSERTINTOtbl_batch3(id,info)VALUES(1,'a'),(2,'b'),(3,'c');INSERT03 数据如下: mydb=> SELECT * FROM tbl_batch3;id | info ---+---1 | a2 | b3 | c(3 rows) 这种批量插入方式非常独特,一条SQL插入多行数据,相比...
Filter: (user_info.userid = 520) Rows Removed by Filter: 99999 Planning Time: 0.041 ms Execution Time: 6.717 ms(6 rows)添加buffers选项postgres=# explain(analyze,verbose,costs,buffers,timing) select * from user_info where userid=520; QUERY PLAN --- Seq Scan on public.user_info (cost=...
Introduced support to correlated subquery transform and cache for enhancement of query performance by transforming scalar correlated subquery into join query, or caching the subquery result set and reduce duplicate subquery re-executions when transformation is not possible. For more information, see Optimiz...
ERROR: duplicate key value violates unique constraint "user_logins_pkey" DETAIL: Key (user_name)=(francs) already exists. 1. 2. 上述SQL试图插入两条数据,其中matiler这条数据不违反主键冲突,而francs这条数据违反主键冲突,结果两条数据都不能插入。PostgreSQL的UPSERT可以处理冲突的数据,比如当插入的数据冲...
101-127:Thorough duplicate ID handling test. This test effectively verifies that the repository correctly enforces uniqueness constraints for question IDs, which is critical for data integrity. 268-287:Good test for pagination limit. This test effectively verifies that the repository respects the limit...
Fixed "Duplicate Field" function in Table Designer, given "unknown column..." error message. Fixed access violation issue during backup process. Fixed altering the inheritance table, given "syntax error at or near "INHERITS" at..." error message for Navicat PostgreSQL version. Upgrade Procedure ...
id | name ---+--- 1 | abc 2 | bcd (2 rows) __xtest__N2=# select * from t; id | name ---+--- 1 | abc 2 | bcd (2 rows) (六)创建一个partition模式的表 Stado -> create table t2 (area_id int,area_name varchar(20),descs text) partitioning key area_id on all; OK...