blocks|key|4203932|text|根据您的需求，这里有几种方法：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4203933|IF+EXISTS+(SELECT+*+FROM+TABLE+WHERE+COLUMN+=+'SOME+VALUE')
++++--INSERT+SOMETHING
ELSE
++++--INSERT+SOMETHING+ELSE|code-block|syntax|javascript|4203934|或者更长一点|4203935|DECLARE+@retVal+int

SELECT+@retVal+=+COUNT(*)+
FROM+TABLE
WHERE+COLUMN+=+'Some+Value'

IF+(@retVal+>+0)
BEGIN
++++--INSERT+SOMETHING
END
ELSE
BEGIN
++++--INSERT+SOMETHING+ELSE
END+|4203936|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

Depending on your needs, here are a couple of ways:

<pre><code>IF EXISTS (SELECT * FROM TABLE WHERE COLUMN = 'SOME VALUE')
 --INSERT SOMETHING
ELSE
 --INSERT SOMETHING ELSE
</code></pre>

Or a bit longer

<pre><code>DECLARE @retVal int

SELECT @retVal = COUNT(*) 
FROM TABLE
WHERE COLUMN = 'Some Value'

IF (@retVal &gt; 0)
BEGIN
 --INSERT SOMETHING
END
ELSE
BEGIN
 --INSERT SOMETHING ELSE
END 
</code></pre>

blocks|key|853097|text|只需使用以下内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|853098|IF((SELECT+count(*)+FROM+table)=0)
BEGIN

....

END|code-block|syntax|javascript|853099|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Simply use the following:

<pre><code>IF((SELECT count(*) FROM table)=0)
BEGIN

....

END
</code></pre>

blocks|key|4686740|text|只要你需要根据大于0的Count来查找它，最好使用下面这样的EXISTS：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4686741|IF+EXISTS+(SELECT+1+FROM+INCIDENTS++WHERE+[Some+Column]+=+'Target+Data')
BEGIN
++++--+TRUE+Procedure
END
ELSE+BEGIN
++++--+FALSE+Procedure
END|code-block|syntax|javascript|4686742|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

As long as you need to find it based on Count just more than 0, it is better to use EXISTS like this:

<pre><code>IF EXISTS (SELECT 1 FROM INCIDENTS WHERE [Some Column] = 'Target Data')
BEGIN
 -- TRUE Procedure
END
ELSE BEGIN
 -- FALSE Procedure
END
</code></pre>

blocks|key|191777|text|如果存在|type|unstyled|depth|inlineStyleRanges|entityRanges|data|191778|IF+exists+(select+*+from+table_1+where+col1+=+'value')
BEGIN
++++--+one+or+more
++++insert+into+table_1+(col1)+values+('valueB')
END
ELSE
++++--+zero
++++insert+into+table_1+(col1)+values+('value')+|code-block|syntax|javascript|191779|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

IF exists

<pre><code>IF exists (select * from table_1 where col1 = 'value')
BEGIN
 -- one or more
 insert into table_1 (col1) values ('valueB')
END
ELSE
 -- zero
 insert into table_1 (col1) values ('value') 
</code></pre>

blocks|key|853046|text|我不太清楚你说的是什么意思|type|unstyled|depth|inlineStyleRanges|entityRanges|data|853047|853048|+"I+cant+find+any+examples+to+help+me+understand+how+I+can+use+this+to+++run+2+different+statements:"|blockquote|offset|length|style|CODE|853049|853050|853051|。它像SWITCH一样使用CASE吗？|853052|select+case+when+totalCount+>=+0+and+totalCount+<+11+then+'0-10'
++++++++++++when+tatalCount+>+10+and+totalCount+<+101+then+'10-100'
++++++++++++else+'>100'+end+as+newColumn
from+(
++SELECT+[Some+Column],+COUNT(*)+TotalCount
++FROM+INCIDENTS
++WHERE+[Some+Column]+=+'Target+Data'
++GROUP+BY+[Some+Column]
)+A|code-block|syntax|javascript|853053|entityMap^0|0|0|1|2S|0|0|0|3|6|D|4|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|V|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|W|8|@$F|X|G|Y|H|I]]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|10|8|@]|9|@]|A|$]]|$1|L|3|M|5|6|7|11|8|@$F|12|G|13|H|I]|$F|14|G|15|H|I]]|9|@]|A|$]]|$1|N|3|O|5|P|7|16|8|@]|9|@]|A|$Q|R]]|$1|S|3|-4|5|6|7|17|8|@]|9|@]|A|$]]]|T|$]]

Not very clear what you mean by 

<blockquote>
 <code>"I cant find any examples to help me understand how I can use this to
 run 2 different statements:"</code>
</blockquote>

. Is it using <code>CASE</code> like a <code>SWITCH</code> you are after? 

<pre><code>select case when totalCount &gt;= 0 and totalCount &lt; 11 then '0-10'
 when tatalCount &gt; 10 and totalCount &lt; 101 then '10-100'
 else '&gt;100' end as newColumn
from (
 SELECT [Some Column], COUNT(*) TotalCount
 FROM INCIDENTS
 WHERE [Some Column] = 'Target Data'
 GROUP BY [Some Column]
) A
</code></pre>

blocks|key|191182|text|一个显而易见的解决方案是运行两个单独的查询，首先选择所有具有count=1的项并运行插入，然后使用count>1选择项并运行第二次插入。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|191183|第二步，如果两个插入相似，您可以将它们组合到一个查询中。|191184|另一种可能是使用游标遍历记录集，并为每一行执行所需的任何逻辑。|191185|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

one obvious solution is to run 2 separate queries, first select all items that have count=1 and run your insert, then select the items with count>1 and run the second insert.

as a second step if the two inserts are similar you can probably combine them into one query.

another possibility is to use a cursor to loop thru your recordset and do whatever logic you need for each line.

blocks|key|4686750|text|对此进行编码的方法有很多，但这里有一种可能的方法。我假设是MS+SQL|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4686751|我们将从获取行数(另一个Quick+Example)开始，然后执行if/else|offset|length|4686752|--+Let's+get+our+row+count+and+assign+it+to+a+var+that+will+be+used
--++++in+our+if+stmt+
DECLARE+@HasExistingRows+int+--+I'm+assuming+it+can+fit+into+an+int
SELECT+@HasExistingRows+=+Count(*)+
+++ELSE+0+--+false
FROM
+++INCIDENTS
WHERE+{Your+Criteria}
GROUP+BY+{Required+Grouping}|code-block|syntax|javascript|4686753|现在我们可以执行If+/+Else逻辑MSDN+Docs了|4686754|--+IF+/+Else+/+Begin+/+END+Syntax
IF+@HasExistingRows+=+0+--+No+Existing+Rows
+++BEGIN
++++++{Insert+Logic+for+No+Existing+Rows}
+++END
ELSE+--+existing+rows+are+found
+++BEGIN
++++++{Insert+logic+for+existing+rows}
+++END|4686755|另一种更快的方法(灵感来自Mahmoud+Gamal的评论)：|4686756|忘记整个变量的创建/赋值-查找"EXISTS“-+MSDN+Docs+2。|4686757|IF+EXISTS+({SELECT+Query})
+++BEGIN
++++++{INSERT+Version+1}
+++END
ELSE
+++BEGIN
++++++{INSERT+version+2}
+++END|4686758|entityMap|0|LINK|mutability|MUTABLE|url|http://mssql101.blogspot.com/2010/08/mssql-select-value-into-variable.html|1|http://msdn.microsoft.com/en-us/library/ms182717.aspx|2|http://msdn.microsoft.com/en-us/library/ms188336.aspx^0|0|C|D|0|0|0|J|9|1|0|0|0|P|B|2|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|17|8|@]|9|@$D|18|E|19|1|1A]]|A|$]]|$1|F|3|G|5|H|7|1B|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|1C|8|@]|9|@$D|1D|E|1E|1|1F]]|A|$]]|$1|M|3|N|5|H|7|1G|8|@]|9|@]|A|$I|J]]|$1|O|3|P|5|6|7|1H|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1I|8|@]|9|@$D|1J|E|1K|1|1L]]|A|$]]|$1|S|3|T|5|H|7|1M|8|@]|9|@]|A|$I|J]]|$1|U|3|-4|5|6|7|1N|8|@]|9|@]|A|$]]]|V|$W|$5|X|Y|Z|A|$10|11]]|12|$5|X|Y|Z|A|$10|13]]|14|$5|X|Y|Z|A|$10|15]]]]

There are many, many ways to code this, but here is one possible way. I'm assuming MS SQL

We'll start by getting row count (Another <a href="http://mssql101.blogspot.com/2010/08/mssql-select-value-into-variable.html" rel="nofollow">Quick Example</a>) and then do if/else

<pre><code>-- Let's get our row count and assign it to a var that will be used
-- in our if stmt 
DECLARE @HasExistingRows int -- I'm assuming it can fit into an int
SELECT @HasExistingRows = Count(*) 
 ELSE 0 -- false
FROM
 INCIDENTS
WHERE {Your Criteria}
GROUP BY {Required Grouping}
</code></pre>

Now we can do the If / Else Logic <a href="http://msdn.microsoft.com/en-us/library/ms182717.aspx" rel="nofollow">MSDN Docs</a>

<pre><code>-- IF / Else / Begin / END Syntax
IF @HasExistingRows = 0 -- No Existing Rows
 BEGIN
 {Insert Logic for No Existing Rows}
 END
ELSE -- existing rows are found
 BEGIN
 {Insert logic for existing rows}
 END
</code></pre>

Another faster way (inspired by Mahmoud Gamal's comment):

Forget the whole variable creation / assignment - look up "EXISTS" - <a href="http://msdn.microsoft.com/en-us/library/ms188336.aspx" rel="nofollow">MSDN Docs 2</a>.

<pre><code>IF EXISTS ({SELECT Query})
 BEGIN
 {INSERT Version 1}
 END
ELSE
 BEGIN
 {INSERT version 2}
 END
</code></pre>

blocks|key|191729|text|如果这是在SQL+Server中，则语法正确；但是，您需要引用COUNT(*)作为嵌套查询中的Total+Count。这将为您提供所需的内容：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|191730|SELECT+CASE+WHEN+TotalCount+>0+THEN+'TRUE'+ELSE+'FALSE'+END+FROM
(
++SELECT+[Some+Column],+COUNT(*)+TotalCount
++FROM+INCIDENTS
++WHERE+[Some+Column]+=+'Target+Data'
++GROUP+BY+[Some+Column]
)+DerivedTable|code-block|syntax|javascript|191731|使用这种方法，您可以将TotalCount赋值给一个变量，然后使用IF+ELSE语句来执行INSERT语句：|191732|DECLARE+@TotalCount+int
SELECT+@TotalCount+=+TotalCount+FROM
(
++SELECT+[Some+Column],+COUNT(*)+TotalCount
++FROM+INCIDENTS
++WHERE+[Some+Column]+=+'Target+Data'
++GROUP+BY+[Some+Column]
)+DerivedTable
IF+@TotalCount+>+0
++++--+INSERT+STATEMENT+1+GOES+HERE
ELSE
++++--+INSERT+STATEMENT+2+GOES+HERE|191733|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

If this is in SQL Server, your syntax is correct; however, you need to reference the COUNT(*) as the Total Count from your nested query. This should give you what you need:

<pre><code>SELECT CASE WHEN TotalCount &gt;0 THEN 'TRUE' ELSE 'FALSE' END FROM
(
 SELECT [Some Column], COUNT(*) TotalCount
 FROM INCIDENTS
 WHERE [Some Column] = 'Target Data'
 GROUP BY [Some Column]
) DerivedTable
</code></pre>

Using this, you could assign TotalCount to a variable and then use an IF ELSE statement to execute your INSERT statements:

<pre><code>DECLARE @TotalCount int
SELECT @TotalCount = TotalCount FROM
(
 SELECT [Some Column], COUNT(*) TotalCount
 FROM INCIDENTS
 WHERE [Some Column] = 'Target Data'
 GROUP BY [Some Column]
) DerivedTable
IF @TotalCount &gt; 0
 -- INSERT STATEMENT 1 GOES HERE
ELSE
 -- INSERT STATEMENT 2 GOES HERE
</code></pre>

While I am searching through my database, I run an INSERT statement if I find that a particular item does not exist, and I run a different INSERT statement if I find one or more of this item.

I am not entirely sure how to use the IF ELSE expressions.

What I have so far is a statement that will count the number of times the target data appears; it will print TRUE if it is greater than 0, if not, it will print FALSE. I can't find any examples to help me understand how I can use this to run two different INSERT statements.

Here is what I have so far:

<pre><code>SELECT CASE WHEN COUNT(*)&gt;0 THEN 'TRUE' ELSE 'FALSE' END
(
 SELECT [Some Column], COUNT(*) TotalCount
 FROM INCIDENTS
 WHERE [Some Column] = 'Target Data'
 GROUP BY [Some Column]
)
</code></pre>

Using IF ELSE statement based on Count to execute different Insert statements

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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当我在数据库中搜索时，如果发现某个特定项不存在，则运行INSERT语句，如果找到一个或多个该项，则运行不同的INSERT语句。我不完全确定如何使用IF ELSE表达式。到目前为止，我得到的是一个语句，它将计算目标数据出现的次数；如果大于0，它将打印TRUE，如果不大于0，它将打印FALSE。我找不到任何示例来帮助我理解如何使用它来运行两个不同的INSERT语句。这是我到目前为止所知道的：SELEC

问根据计数使用IF ELSE语句执行不同的Insert语句
EN

回答 8

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问根据计数使用IF ELSE语句执行不同的Insert语句EN

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问根据计数使用IF ELSE语句执行不同的Insert语句
EN