一.问题 Postgresql中无则插入的使用方法INSERT INTO WHERE NOT EXISTS,用法请参考样例. 二.解决方案 (1)PostgresSQL INSERT INTO test_tab(name,sex,address,lastEndTime,createTime) SELECT , FROM () tmp WHERE NOT EXISTS (Select FROM test_tab ') (2)MySQL(使用系统临时表DUAL) INSERT INTO `test_
?INSERT sets an exclusive lock on the inserted row. This lock is an index-record lock, not a next-key lock (that is, there is no gap lock) and does not prevent other sessions from inserting into the gap before the inserted row INSERTS 设置一个排他锁在插入的记录,锁
标识符和关键词 受限标识符或被引号修饰的标识符.它是由双引号(")包围的一个任意字符序列.一个受限标识符总是一个标识符而不会是一个关键字.因此"select"可以用于引用一个名为“select”的列或者表,而一个没有引号修饰的select则会被当作一个关键词,从而在本应使用表或列名的地方引起解析错误.在上例中使用受限标识符的例子如下:UPDATE "my_table" SET "a" = 5; 在PostgreSQL关系型数据库中存在关
Following is test in SQL Server: USE [TestDB] CREATE TABLE [dbo].[UserInfoTest02]( [number] [bigint] NOT NULL, ) NOT NULL, [age] [int] NOT NULL, [sex] [bit] NOT NULL, ) NULL ) CREATE TABLE [dbo].[UserInfoTest03]( [number] [bigint] NOT NULL, ) NOT NUL
1.postgresql 查询每组第一个 ROW_NUMBER () OVER (partition by 字段 ORDER BY 字段 DESC) 写法:SELECT ROW_NUMBER () OVER (partition by 字段 ORDER BY 字段 DESC) AS 字段别名 FROM 表名: SELECT * FROM (SELECT *,ROW_NUMBER () OVER (partition by 字段 ORDER BY 字段 DESC) AS