sql case statement
In this tutorial, you will learn how to use SQL UPDATE statement to change existing data in a table.
2.举例: SELECTOrderID, Quantity,CASEWHENQuantity>30THEN'The quantity is greater than 30'WHENQuantity=30THEN'The quantity is 30'ELSE'The quantity is under 30'ENDASQuantityTextFROMOrderDetails; SELECTCustomerName, City, CountryFROMCustomersORDERBY(CASEWHENCityISNULLTHENCountryELSECityEND); 以上例子等...
SQL还可以在一个SELECT语句或UPDATE语句中,表达与面向过程语言一样非常复杂而且灵活的条件分支,不过这需要借助CASE表达式。 之所以叫它CASE“表达式”而不是CASE“语句”(statement),是因为CASE表达式与1+(2-4)或者(x*y)/z一样,都是表达式,在执行时会被整体当作一个值来处理。既然同样是表达式,那么能写1+1这样...
SELECTTOP10qs.last_execution_time, st.textASbatch_text,SUBSTRING(st.TEXT, (qs.statement_start_offset /2) +1, ((CASEqs.statement_end_offsetWHEN-1THENDATALENGTH(st.TEXT)ELSEqs.statement_end_offsetEND- qs.statement_start_offset) /2) +1)ASstatement_text, (qs.total_worker_time /1000) / ...
are checkedformatches,anda row thatisnotinanyofthese partitionsorsubpartitionsisnotupdated, whether it satisfies the where_conditionornot.*Note*: Unlike thecasewhenusing PARTITIONwithanINSERTorREPLACEstatement, an otherwise validUPDATE... PARTITION statementisconsidered successful evenifno rowsinthe listed...
sql_statement_recompile扩展事件 (XEvent) 报告语句级重新编译。 当任何类型的批处理需要语句级重新编译时,会发生此 XEvent。 这包括存储过程、触发器、即席批处理和查询。 可通过几个接口来提交批处理,这类接口包括 sp_executesql、动态 SQL、“准备”方法或“执行”方法。
CASEcan be used in any statement or clause that allows a valid expression. For example, you can useCASEin statements such as SELECT, UPDATE, DELETE and SET, and in clauses such as, IN, WHERE, ORDER BY, and HAVING. Transact-SQL syntax...
数据泵导入需要 dmp 文件才可以,执行 insert 语句插入需要 .sql 文件才行,当然外部表的形式也可以,但外部表没法编辑且文件位于数据库外,不能 update 编辑数据则考虑 sqlldr 直接加载到 Oracle 数据库中更为方便。 SQL*Loader 原理 将外部数据(比如文本型)导入Oracle 数据库中。(可用于不同类型数据库数据迁移)...
The SQL CASE statement is used to check conditions and perform tasks on each row while selecting data. In this tutorial, you will learn about the SQL CASE statement with the help of examples.