IF THEN in SQL SELECT Statement I recently came across the CASE WHEN statement work Similar to IF statement into SQL SELECT , Maybe you’ll find it useful. Create table called Student using SQL Query: CREATE TABLE [dbo].[Student]( [StudentID] [int] NULL, [Marks] [float] NULL ) Inse...
SQL SELECT 语句 SELECT 语句用于从表中选取数据。 结果被存储在一个结果表中(称为结果集)。...SQL SELECT 语法 SELECT 列名称 FROM 表名称 以及: SELECT * FROM 表名称 注释:SQL 语句对大小写不敏感。SELECT 等效于 select。...SQL SELECT 实例 如需获取名为 "LastName" 和 "FirstName" 的列的...
In SQL Server there is anIF…ELSE control flow statement. However, it cannot be used inside a SELECT statement. The closest of IF…THEN operation which can be used in SELECT statements is CASE expression or the IIF function. Let us see how to use CASE and IIF using an example. For thi...
PUT_LINE('逗号数量:' || SIGNS); --赋最大值 SI_MAX := SIGNS; --循环拼接SQL WHILE SIGNS > 0 LOOP --取当前字段 SELECT SUBSTR(STR,1,INSTR(STR,',') - 1 ) INTO CURRENT_VALUE FROM DUAL; --在待拼接的字段里删除当前字段 SELECT SUBSTR(STR,INSTR(STR,',') + 1) INTO STR FROM DUAL...
SQL If Statement In this tutorial, you will learn how to write Conditional statements – IF and IF-ELSE. In real-world situations, we used to do something according to the result of something we expect. Say for example, “If tomorrow is a holiday, I’ll plan for a vacation”, “If ...
Use the IF statement within PL/SQL contexts to execute SQL statements on the basis of certain criteria.
create procedure p(inout score double) begin set score := score * 0.5; end; set @score = 198; call p(@score); select @score;case介绍case结构及作用,和我们之前的流程控制函数很类似。有两种语法格式:语法一:/* 含义: 当case_value的值为 when_value1时, 执行statement_list1,当值为 when_...
IF Boolean_expression { sql_statement | statement_block } [ ELSE { sql_statement | statement_block } ]Boolean_expression: A boolean expression that returns TRUE or FALSE. If the Boolean expression contains a SELECT statement then it should be enclosed in parentheses. ...
{ sql_statement | statement_block } ] 参数说明: Boolean_expression返回True或False的表达式。如果布尔表达式包含SELECT语句,则SELECT语句必须用括号括起来 { sql_statement | statement_block }使用语句块定义的任何有效的Transact-SQL语句或语句分组。要定义语句块(批处理),请使用流语言关键字BEGIN和END 组合。尽...
In this example, we select a film by a specific film id (0). The found is a global variable that is available in PL/pgSQL. The select into statement sets the found variable if a row is assigned or false if no row is returned. We use the if statement to check if the film with ...