Web28 Feb 2024 · The Transact-SQL statement that follows an IF keyword and its condition is executed if the condition is satisfied: the Boolean expression returns TRUE. The optional … WebWHERE 子句 如需有条件地从表中选取数据,可将 WHERE 子句添加到 SELECT 语句。 语法 SELECT 列名称 FROM 表名称 WHERE 列 运算符 值 下面的运算符可在 WHERE 子句中使 …
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Web4 Apr 2024 · NOT IN、JOIN、IS NULL、NOT EXISTS效率对比 语句一:select count(*) from A where A.a not in (select a from B) 语句二:select count(*) from A left join B on A.a = B.a … Web27 Oct 2024 · Oracle中,在WHERE子句后面加入IF语句的语法为: ``` SELECT column1, column2 FROM table WHERE (condition1 AND condition2) IF condition3 THEN column3 … did a key job in providing a change of air
一文讲懂SQL条件语句 IF函数 - 知乎
Web17 Sep 2008 · 2) Use IF's outside the SELECT IF (IsNumeric (@OrderNumber)) = 1 BEGIN SELECT * FROM Table WHERE @OrderNumber = OrderNumber END ELSE BEGIN SELECT … Webopen:代表语句的开始部分 close:代表结束部分 item:代表遍历集合的每个元素,生成的变量名 sperator:代表分隔符. 4. 代码片段的定义与引用. Sql 中可将重复的 sql 提取出来,使用时 … Web16 Sep 2024 · mysql查询语句where后面加if判断 说明:WHERE IF (条件, true执行条件, false执行条件 ) SELECT * FROM book WHERE IF (price > 120, btypeid =10, btypeid =11 ); … did akbar marry his mother