SQL技术求助：如何将HTML标签清理函数嵌入数据查询

Hey there! Let's walk through how to use this HTML-cleaning function in your SQL queries step by step—no stress, I'll break it down so it makes sense.

Before you can use the function, you need to add it to your database's dbo schema. Grab the full function code (including the part you truncated with ...) and run this script in your SQL tool (like SSMS or Azure Data Studio):

CREATE FUNCTION [dbo].[mcl_RemoveVisionMemoFormat] (@String NVARCHAR(MAX)) 
RETURNS NVARCHAR(MAX) 
AS 
BEGIN 
    declare @start int, @end int, @length int 
    while charindex('<', @string) > 0 and charindex('>', @string, charindex('<', @string)) > 0 
    begin 
        select @start = charindex('<', @string), 
               @end = charindex('>', @string, charindex('<', @string))
        -- Make sure to include the rest of the logic from your full function here
        -- A common way to remove the tag is with STUFF(), like this:
        set @string = stuff(@string, @start, @end - @start + 1, '')
    end
    return @string
END

Quick note: I added the STUFF() line as a standard way to strip the HTML tag substring. If your full function has different logic for removing the tags, replace that line with whatever was in the original code you received!

Once the function is created, you can call it just like any built-in SQL function. Here are a few common use cases:

Basic Select (View Cleaned Text) #

If you have a table (say, CustomerNotes) with a column (NoteContent) full of HTML-formatted text, you can pull the cleaned version alongside the original:

SELECT 
    OriginalNote = NoteContent,
    CleanedNote = [dbo].[mcl_RemoveVisionMemoFormat](NoteContent)
FROM 
    CustomerNotes
WHERE 
    NoteContent IS NOT NULL

Use in a Filter #

You can even use the cleaned text to filter results. For example, find notes that mention "shipping" after stripping HTML:

SELECT 
    CustomerID,
    [dbo].[mcl_RemoveVisionMemoFormat](NoteContent) AS CleanedNote
FROM 
    CustomerNotes
WHERE 
    [dbo].[mcl_RemoveVisionMemoFormat](NoteContent) LIKE '%shipping%'

Update a Column to Store Cleaned Text #

If you want to save the cleaned text permanently (instead of calculating it every time), use an UPDATE statement:

UPDATE CustomerNotes
SET CleanedNoteContent = [dbo].[mcl_RemoveVisionMemoFormat](NoteContent)
WHERE NoteContent IS NOT NULL

• This function targets escaped HTML tags (< and >). If your data has unescaped < and > instead, you'll need to adjust the CHARINDEX calls to look for those characters directly.
• Since it uses NVARCHAR(MAX), it can handle large blocks of text without issues.
• Make sure you have permission to create functions in your database—if you get an error, check with your DBA.

内容的提问来源于stack exchange，提问作者user3740736