大约有 44,000 项符合查询结果(耗时:0.0643秒) [XML]

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Eloquent Collection: Counting and Detect Empty

This may be a trivial question but I am wondering if Laravel recommends a certain way to check whether an Eloquent collection returned from $result = Model::where(...)->get() is empty, as well as counting the number of elements. ...
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Is there a better way to dynamically build an SQL WHERE clause than by using 1=1 at its beginning?

I'm building some SQL query in C#. It will differ depending on some conditions stored as variables in the code. 22 Answer...
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What is the correct syntax for 'else if'?

...om 2.6.4 to 3.1.1. Everything has gone fine until I tried to use the 'else if' statement. The interpreter gives me a syntax error after the 'if' in 'else if' for a reason I can't seem to figure out. ...
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Kotlin Ternary Conditional Operator

... In Kotlin, if statements are expressions. So the following code is equivalent: if (a) b else c The distinction between expression and statement is important here. In Java/C#/JavaScript, if forms a statement, meaning that it does not ...
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Check if table exists in SQL Server

I would like this to be the ultimate discussion on how to check if a table exists in SQL Server 2000/2005 using SQL Statements. ...
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How to avoid 'cannot read property of undefined' errors?

... Update: If you use JavaScript according to ECMAScript 2020 or later, see optional chaining. TypeScript has added support for optional chaining in version 3.7. // use it like this obj?.a?.lot?.of?.properties Solution for JavaScr...
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How to find out if an item is present in a std::vector?

...ind(vec.begin(), vec.end(), item) != vec.end() This returns a bool (true if present, false otherwise). With your example: #include <algorithm> #include <vector> if ( std::find(vec.begin(), vec.end(), item) != vec.end() ) do_this(); else do_that(); ...
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Create PostgreSQL ROLE (user) if it doesn't exist

...QL script to create a ROLE in PostgreSQL 9.1, but without raising an error if it already exists? 10 Answers ...
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Check if two unordered lists are equal [duplicate]

I'm looking for an easy (and quick) way to determine if two unordered lists contain the same elements: 8 Answers ...
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if…else within JSP or JSTL

... Should I use JSTL ? Yes. You can use <c:if> and <c:choose> tags to make conditional rendering in jsp using JSTL. To simulate if , you can use: <c:if test="condition"></c:if> To simulate if...else, you can use: <c:choose> <c:wh...