The relationship is specified with a delete rule of RESTRICT or SET NULL and would cause the two tables to be delete-connected to each other. The relationship is specified with a delete rule of CASCADE and would
set odps.sql.executionengine.batch.rowcount=16; divide.nan.or.overflow 旧版MaxCompute不会做除法常量折叠的问题。 比如如下语句,旧版MaxCompute对应的物理执行计划如下: explain select if(false, 0/0, 1.0) from table_name; in task M1_Stg1: Data source: meta_dev.table_name TS: alias: table_name...
将ANSI_DEFAULTS 设置为 OFF 的执行具有新的 plan_handle,并且它可用于对具有一组相同的 SET 选项的调用。 新的计划句柄是必需的,因为由于 SET 选项已更改,执行上下文已重新初始化。 但这并不会触发重新编译:这两个条目引用相同的计划和查询,相同的 query_plan_hash 和query_hash 值可证明。这实际上意味着,在...
SQL Server Pivot Table on two columnsYou can use dynamic T-SQL in order to make a pivot for ...
更新:update table1 set field1=value1 where范围 查找:select * from table1 where field1 like ’%value1%’ ---like的语法很精妙,查资料! 排序:select * from table1 order by field1,field2 [desc] 总数:select count as totalcount from table1 ...
-- Returns only two of the columns from the tableSELECTProductName, PriceFROMdbo.ProductsGO 使用WHERE子句可以限制返回给用户的行。 SQL -- Returns only two of the records in the tableSELECTProductID, ProductName, Price, ProductDescriptionFROMdbo.ProductsWHEREProductID <60GO ...
DECLARE@ColumnsNVARCHAR(MAX);DECLARE@SQLNVARCHAR(MAX);-- 获取所有不同的产品名称SELECT@Columns=STRING_AGG(QUOTENAME(Product),',')FROM(SELECTDISTINCTProductFROMSales)ASProducts;-- 动态构建 SQL 查询SET@SQL=N' SELECT Region, '+@Columns+'
Because DISTINCT may use GROUP BY, learn how MySQL works with columns in ORDER BY or HAVING clauses that are not part of the selected columns. See Section 12.20.3, “MySQL Handling of GROUP BY”. 因为distinct可能使用group by,了解MySQL如何处理按order by 列或者具有不属于所选列的子句。见12.2...
This example calculates the number of day boundaries crossed between dates in two columns in a table. SQL CREATETABLEdbo.Duration ( startDate DATETIME2, endDate DATETIME2 );INSERTINTOdbo.Duration (startDate, endDate)VALUES('2007-05-06 12:10:09','2007-05-07 12:10:09');SELECTTOP (1)DAT...
Histograms in SQL Server are only built for a single column-the first column in the set of key columns of the statistics object. To create the histogram, the Query Optimizer sorts the column values, computes the number of values that match each distinct column value, and then aggregates the...