In this tutorial, we will look at the workings of the LIKE clause and how we can use it to specify multiple conditions. Sample Data For this tutorial, we are going to use a simple database with minimal data. The full query to create the data is as shown below: ...
It turned out that many entries in the table 1 and table 2 had string_field column with NULL values. I thought that JOIN would keep records with NULL values because NULL is equal to NULL, isn’t it? Then I tried: 代码语言:javascript 代码运行次数:0 运行 AI代码解释 SELECTNULL=NULL It ...
SQL Multiple Insert可以通过以下方式实现: 使用INSERT INTO语句的多个值列表:可以在INSERT INTO语句中指定多个值列表,每个值列表对应一行数据。例如: 代码语言:sql 复制 INSERT INTO table_name (column1, column2, column3) VALUES (value1, value2, value3), (value4, value5, value6), (value7, value8,...
WHERE agent_code='A002': This line specifies a condition for filtering the results. It filters the results to only include rows where the value in the 'agent_code' column is 'A002'. This condition acts as a filter, allowing only rows with 'A002' as the agent code to be included in t...
With full SQL-92,0 values has a richer semantic: it becomes valid wherever select is valid and can produce multiple rows. Usage with Full SQL-92 With full SQL-92, values is generally1 followed by a comma separated list of rows that are in turn column lists enclosed in parentheses. Each...
When working in SQL databases, you may encounter such instances where you must find the distinct values from a given table and remove the duplicate values. In most cases, we mainly use the distinct clause to specify the column whose values are what we wish to be unique. ...
PostgreSQL supports string manipulation, which makes it easier to split column values into multiple columns. We’ll explore using the SPLIT_PART and STRING_TO_ARRAY functions to achieve this. 4.1. Using SPLIT_PART Function The SPLIT_PART function allows us to extract a substring from a string ...
In the below example, we retrieve data from all columns with where condition. We use the id, name, city, and phone column to retrieve the data. After using a distinct clause on all columns with the where condition, it will retrieve the unique values from the rows we defined in the wher...
报错:null value in column "xxx" violates not-null constraint 问题原因:违反非空约束,NOT NULL的列写入了NULL值。 解决方法:去掉NULL的脏数据后再进行写入。 ERRCODE_UNDEFINED_TABLE 报错:Dispatch query failed: Table not found 问题原因:表不存在,一般出现在表刚刚创建未更新元数据或者Query执行过程中,表执行...
Multiple Active Result Sets (MARS) 支援列存儲索引。 全新動態管理檢視sys.dm_db_column_store_row_group_physical_stats (Transact-SQL)提供資料列群組層級的效能疑難排解資訊。 數據行存放區索引上的所有查詢都可以在批次模式中執行。 先前,只有平行查詢可以在批次模式中執行。