Generate and execute SQL scripts 1. Generate the database2. Generate SQL script from the data table4. Execute SQL script 1. Generate the database Quickly create scripts for entire data using the Object Explorer, or for individual database objects using default options;Users canQuery editor windowCreate scripts for files or clipboards in Unicode format;Users can also create scripts for creating or ... »
The company’s business needs to import more than 100,000 pieces of data in the Excel table into the database table, which is much faster than executing SQL statements to insert dataFor example: I want to import the (sanyi.xlsx) Excel table as shown below into the MySQL table (tb_sanyi_client) 1. Save the excel table as a csv file, csv is comma-separated by default 2. Use the notepad++ tool t... »
ClickHouse query statements are compatible with most SQL grammars and have been extended more abundantly. The query statement templates are as follows: [WITH expr_list|(subquery)] SELECT [DISTINCT [ON (column1, column2, ...)]] expr_list [FROM [db.]table | (subquery) | table_function] [FINAL] [SAMPLE sample_coeff] [ARRAY JOIN ...] [GLOBAL] [ANY|ALL|ASOF] [INNER|LEFT|RIGHT|FULL|CROSS] [OUTER|SEMI|A... »
Homepage:Homepage Series of columns:MySQL database Reminder: This blog is more comprehensive, please bookmark it in case you can’t find it At 3:30 in the night battle with the lights on, I wrote 4w words with a pen and a pen, just for Bojun to see twice! previous section directory 1. Mysql download, install and start (suitable for friends who have not downloaded and followed MySQL, super detaile... »
Methods provided by mybatisplus: orderBy(boolean, boolean, String… columns) orderByAsc(boolean, String… columns) orderByAsc(String) orderByAsc(String… columns) orderByDesc(boolean, String… columns) orderByDesc(String) orderByDesc(String… columns) Use the first method to achieve multi-field custom sorting： com.baomidou.mybatisplus.core.conditions.query.QueryWrapper<... »
The compiler uses IDEA My related blogs: The method and code of connecting to the mysql database in the java code program Mysql database concurrent locking problem, java code 1. Use the MySQL jdbc connector mysql-connector-java.jar. 1. First download from the mysql official websitemysql-connector-java.jarPackage to local.Be careful here to match your local mysql database version! Download the corr... »
Table of contents 1. The syntax and usage of the substring_index function (1) Syntax: substring_index(string,sep,num) (2) Used to intercept the target string. 2. Examples (1) Intercept the target string from a field. (2) Used in combination with the cast function to intercept a string and convert it to the target format. 1. The syntax and usage of the substring_index function (1) Syntax: substring... »
Visual Studio2022 connects to SQL Server database 1. Software preparation1. Install Visual Studio 2022 Second, prepare for the database connection1. Create a database2. Use ODBC to establish a connection 3. Connect to the database1.Visual Studio2022 test connection database This article is based on Visual Studio2022 and SQL Server2008 to connect the database with the backend through ODBC. 1. Softw... »
Table of contents foreword 1. Time addition and subtraction 1. Time variable operation 2.date_add() 3. date_sub() 4.period_add() 5.period_diff(P1,P2) 6.datediff(date1,date2) 7.timediff(time1,time2) 8.time_to_sec()、sec_to_time() 9.to_days(date),from_days(days) 10.time_formate 2. Time format matching 1.get_format() 2.substr() Pay attention to prevent getting lost, if there are any mistakes, plea... »
Article Directory Inner connection (join)Outer join (left join)The difference between on and whereself-joinsubqueries (nested queries)Merge query (union) 1. Pre-knowledge – Cartesian product In actual development, data often comes from different tables, so multi-table joint query is required. Multi-table query is to take the Cartesian product of data in multiple tables.Cartesian product is t... »
