1是常量，在这里只是代表存在 如果inserted或deleted表中无数据，那么select不会出数据 如果表中有数据，select会显示1 这里写1与*作用相同，exists只判断是否有数据，不会将数据输出
--如果存在表 tb_stu ,先删除在重新创建droptableifexiststb_stu;--与where子句一块使用select···from表名whereexists(子查询); exists 关键字后面的参数是一个任意的子查询,如果该子查询有返回行,则exists子查询结果为true,此时在执行外层查询语句 如果子查询没有返回行,则exists 子查询的结果为false,此时不...
--如果存在表 tb_stu ,先删除在重新创建droptableifexiststb_stu;--与where子句一块使用select···from表名whereexists(子查询); exists 关键字后面的参数是一个任意的子查询,如果该子查询有返回行,则exists子查询结果为true,此时在执行外层查询语句 如果子查询没有返回行,则exists 子查询的结果为false,此时不...
判断是否存在名为staffinfo的用户表，若不存在执行if语句块中的语句
But the code you added in the last step calls theoriginalRange.textproperty, and this is a significant difference from the earlier functions you wrote, because theoriginalRangeobject is only a proxy object that exists in your task pane's script. It doesn't know what the actual text of the...
public:bool rowExists()- test whether theXLRowIteratorcurrently points to a row that already exists in the XML public:bool endReached()- equivalent to (XLRowIterator) it == (XLRowRange) range.end() public:uint32_t rowNumber() const- return the current row that the iterator is pointing ...
Gold's Cards- Adds the enhancement "Rainbow Cards" to the game, which give 3x mult, as well as 4 new tarot cards and 1 new spectral. by@Goldfighter5 Functionality GUI Jokers Seals Suits Tags Tags Preview- Uncommon, Rare, Foil, Holographic, Polychrome and Negative Tags show the Joker you...
Open a new query editor: Press Ctrl+N to open a new query editor, or right-click on your server and select New Query. Create the database by pasting the following snippet into the query editor and selecting Run: SQL 复制 IF NOT EXISTS (SELE...
MySQL> select distinct count(1) from test1 where exists (select * from test2 where test2.a=test1.a) group by a; +---+ | count(1) | +---+ | 1 | +---+ 1 row in set (0.00 sec) MySQL> select count(distinct a) from test1 where exists (select * from test2 where...
The versioning feature is now available in COS. If versioning is not enabled for the bucket, when you upload a new file to a bucket in which another file of the same name already exists, the older one will be directly overwritten; if versioning is enabled, multiple versions of the object...