一、 MySQL建表，字段需设置为非空，需设置字段默认值。二、 MySQL建表，字段需NULL时，需设置字段默认值，默认值不为NULL。三、 MySQL建表，如果字段等价于外键，应在该字段加索引。四、 MySQL建表，不同表之间的相同属性值的字段，列类型，类型长度，是否非空，是否默认值，需保持一致，否则无法正确使用索引进行关联对比。五、 MySQL使用时，一条SQL语句只能使用一个表的一个索引。所有的字段类型都可以索引，多列索引的属性最多15个。六、 如果可以在多个索引中进行选择，MySQL通常使用找到最少行的索引，索引唯一值最高的索引。七、 建立索引index（part1,part2,par
2022-03-26 13:03:51
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通过获取的数据，将数据进行相关的规则处理生成不同的sql建表文件；
使用方法：new Data2Sql(data,type);
data：获取的数据；
type：转换的类型文件 ，如：mysql,sqlserver,oracle(目前仅支持此三种数据库)；
此文件也可以配合本人的 GetExcelData.js 工具一起使用；
GetExcelData.js 用来读取Excel文件数据，
2022-03-17 11:24:13
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资源包括：19道SQL语句查询题目及答案、建表SQL语句、题目相关的表截图。答案中除了包含intersect、except关键词的答案，其余都在MySQL上跑过，确保运行无误（MySQL不支持intersect、except关键词），因为脑细胞死得有些多，资源分不少请大家见谅。
题目如下：
Q:Find all customers who have both an account and a loan at the Perryridge branch.(ps:MySQL不支持intersect运算符)
Q:Find the number of depositors for each branch.
Q:Find the names of all branches where the average account balance is more than $1,200.
Q:Find the names of all branches that have greater assets than all branches located in Brooklyn.
Q:Find all accounts with the maximum balance.
Q:Find all branches that have greater assets than some branch located in Brooklyn.
Q:Find all customers who have both an account and a loan at the bank.
Q:Find all customers who have accounts at all branches located in Brooklyn.
Q:Find the average account balance at the Perryridge branch.
Q:Find the number of tuples in the customer relation.
Q:Find the number of depositors in the bank.
Q:Find the number of depositors for each branch.
Q:Find all customers who have a loan at the bank but do not have an account at the bank.
Q:Find all branches where the total account deposit is greater than the average of the total account deposits at all branches.
Q:Find all customers who have both an account and a loan at the bank.
Q:Find all customers who have at most one account at the Perryridge branch.
Q:Provide as a gift for all loan customers of the Perryridge branch, a $200 savings account. Let the loan number serve as the account number for the new savings account.
Q:Increase all accounts with balances over $10,000 by 6%, all other accounts receiver 5%.
2022-03-16 19:51:17
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以前一直早不到,直到一朋友做一个ga项目时才整理出来的,2018最新省市区包含台湾省sql,最新省市区建表sql
2022-02-11 15:04:21
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