大约有 44,000 项符合查询结果(耗时:0.0158秒) [XML]

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Can you have if-then-else logic in SQL? [duplicate]

I need to do select data from a table based on some kind of priority like so: 7 Answers ...
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Oracle SQL: Update a table with data from another table

...his is called a correlated update UPDATE table1 t1 SET (name, desc) = (SELECT t2.name, t2.desc FROM table2 t2 WHERE t1.id = t2.id) WHERE EXISTS ( SELECT 1 FROM table2 t2 WHERE t1.id = t2.id ) Assuming the join results in a key-pr...
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What is the simplest SQL Query to find the second largest value?

... SELECT MAX( col ) FROM table WHERE col < ( SELECT MAX( col ) FROM table ) share | improve this answ...
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Change the selected value of a drop-down list with jQuery

... jQuery's documentation states: [jQuery.val] checks, or selects, all the radio buttons, checkboxes, and select options that match the set of values. This behavior is in jQuery versions 1.2 and above. You most likely want this: $("._statusDDL").val('2'); ...
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Blank HTML SELECT without blank item in dropdown list

... Just use disabled and/or hidden attributes: <option selected disabled hidden style='display: none' value=''></option> selected makes this option the default one. disabled makes this option unclickable. style='display: none' makes this option not displayed in older ...
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How do SQL EXISTS statements work?

... criteria -- this is why it can be faster than IN. Also be aware that the SELECT clause in an EXISTS is ignored - IE: SELECT s.* FROM SUPPLIERS s WHERE EXISTS (SELECT 1/0 FROM ORDERS o WHERE o.supplier_id = s.supplier_id) ...should hit a division by zero error...
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SQL - Select first 10 rows only?

How do I select only the first 10 results of a query? 12 Answers 12 ...
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MySQL: selecting rows where a column is null

I'm having a problem where when I try to select the rows that have a NULL for a certain column, it returns an empty set. However, when I look at the table in phpMyAdmin, it says null for most of the rows. ...
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How to drop all tables in a SQL Server database?

...VARCHAR(500) DECLARE @Cursor CURSOR SET @Cursor = CURSOR FAST_FORWARD FOR SELECT DISTINCT sql = 'ALTER TABLE [' + tc2.TABLE_SCHEMA + '].[' + tc2.TABLE_NAME + '] DROP [' + rc1.CONSTRAINT_NAME + '];' FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc1 LEFT JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS t...
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SQL Server SELECT INTO @variable?

... You cannot SELECT .. INTO .. a TABLE VARIABLE. The best you can do is create it first, then insert into it. Your 2nd snippet has to be DECLARE @TempCustomer TABLE ( CustomerId uniqueidentifier, FirstName nvarchar(100), LastNa...