Oracle SQL about Case-when,if-then,decode

Today, when collecting 58-second-hand market data, there is a problem: the style of the Web page is not enough to standardize the data collected, the specific data table is as follows:

This data is not conducive to observation, nor can it be used for analysis. I use Case-when to carry out the preliminary cleaning. (startindex and Endindex in substr need to count ~)

Select         Case  whenT.condition like '<!---color-->%'  Thensubstr (t.condition, -, Length (t.condition)-  -) whent.condition like 'Color:%'  Thensubstr (t.condition, A, Length (t.condition)-  -)Else '\ n' ENDCONDITION, T.classification2, Case  whenT.release_date like '<li class= "Time" title= "Release date" >%'  Thensubstr (T.release_date, to, Length (t.release_date)- *) whent.release_date like '<li class= "Time" >%'  Thensubstr (T.release_date, -, Length (t.release_date)- A) whent.release_date like 'Update Time%'  Thensubstr (T.release_date,6, Length (t.release_date))Else '\ n' ENDRelease_date, Case  whenT.price like '<span%>'  Thensubstr (T.price, -, Length (T.price)- the) whenT.price like '%<'  Thensubstr (T.price, -, Length (T.price)- $)||SUBSTR (T.price,length (T.price)-2, LENGTH (T.price)) whenT.price like 'Price:%'  ThenSUBSTR (T.price, -, LENGTH (T.price)- *)ELSE '\ n' ENDPrice , Case  whenT.sellername like 'linkman%" "  Thensubstr (T.sellername,Ten, Length (T.sellername)-Ten) whenT.sellername like 'linkman%>'  Thensubstr (T.sellername,Ten, Length (T.sellername)-185)Else '\ n' EndSellername fromTABLENAME T

The resulting data is more normative:

Thus, we can summarize the following case-when syntax:

 Case  when Condition1  Then Sentence1  when Condition2  Then Sentence2 ... ELSE Sentencen END

In addition, If-then-elif-else can also be used.

At first I thought Decode was not applicable here because decode (condition, value 1, translation value 1, value 2, translation value 2,... Value n, translation value n, default value)

The function has the following meanings:
IF condition = value 1 Then
RETURN (translation value 1)
elsif condition = value 2 Then
RETURN (translation value 2)
......
elsif condition = value n Then
RETURN (translated value N)

ELSE
RETURN (default value)
END IF

And I need the condition like value.

Later access to Data discovery: You can decode combine InStr function to achieve "conditional like value":

InStr (STR1,STR2), meaning that if str1 contains str2, returns the position of str2 in str1, otherwise returns 0.

However, this method is not recommended because only Oracle has the DECODE function, which is not good enough in other databases.

Finish.

Oracle SQL about Case-when,if-then,decode