mysql - Which SQL query is better, MATCH AGAINST or LIKE? -


To find the database of those rows in which "foo" and "bar" both in one of the "foo_desc" columns The keywords "Bar_desc" will do something like: 

  SELECT * T1 from WHERE MATCH (t1.foo_desc, t2.bar_desc) ('+ foo * + bar *' in bullion mode) < '% Foo%' like / code>  
 or  
  SELECT * to T1 WHERE (CONCAT (t1.foo_desc, t2.bar_desc) and (CONCAT (t1 . Foo_desc, t2.bar_desc) '<% bar%')  
 
 I hope the negative side of the last query is displayed. 
 
 It is upwards that a query like 'Xxfoo' is where the match does not occur. 
 
 Which is the priority or the better solution?

update

MySQL 5.6 Later, InnoDB supports tables against matching ... against .

The first lot will use the full text index against those columns on the better MyISAM tables. Second, one is contacting every line and after that a full table will scan.

Likes only if you are against it:

  • There is no result of a column (function, unless your specific database The vendor does not support the functional index - for example - Oracle - and you are using them);
  • The beginning of the column (like as opposed to 'Blah%' as '% blah%' );
  • is a indexed column.

If none of those conditions is true then the only way to execute the query to the SQL engine is to scan the whole table. It can be useful under approximately 10-20 thousand rows

Note: There is a problem with MATCH on MySQL that it seems that matches only with full words Therefore, 'bla' will not be searched for a column with the values ​​of 'bla', but will be searched for 'bla *'.


Comments

Post a Comment

Popular posts from this blog

python - Overriding the save method in Django ModelForm -

I'm having trouble overriding a ModelForm save method. I get this error I'm: Exception type: TypeErier Exception Value: Save () found an unexpected keyword argument 'committed' My intentions include a form 3 fields Submit several values ​​for, then create an object for each combination of those areas, and to save each object file models.py class collarsult type (models.Model): id = model. AutoField (db_column = 'icontact_result_code_type_id', primary_key = true) callResult = models.ForeignKey ( 'CallResult', db_column = 'icontact_result_code_id') campaign = models.ForeignKey ( 'campaign', db_column = 'icampaign_id') CALLTYPE = models.ForeignKey ( 'CALLTYPE', db_column = 'icall_type_id') agent = models.BooleanField (db_column = 'bagent', default = true) teamLeader = models.BooleanField (db_column = 'bTeamLeader', default = true) active = models.BooleanField (db_column = Django.form...
Read more

html - CSS autoheight, but fit content to height of div -

I have a div in which there are three children- div in the left and middle div: float: left while true: float: true because it is my layout Actually will spoil, I've used ClearFix Hack: .cf {zoom: 1; }. Cf: First,. Cf: {content: ""; Display: Table; }. Cf: After {clear: both; } It still works, but I want to be the right div an indicator. So it should fill 100% of the parent unit of height. How can I complete this? PS is the full code: & Lt; / Div & gt; & Lt; Div class = "mobile_content" & gt; & Lt; H5 & gt; {{Data.titel}} & lt; / H5> & Lt; Table & gt; & Lt; TR & gt; & Lt; Th & gt; Komponist: & lt; / Th & gt; & Lt; TD & gt; {{Data.komponist}} & lt; / TD & gt; & Lt; / TR & gt; & Lt; TR & gt; & Lt; Th & gt; Instrument: & lt; / Th & gt; & Lt; TD & gt; {{Data.instrumente}} & lt; / TD & gt; & Lt; / TR & gt;...
Read more

qt - How to prevent QAudioInput from automatically boosting the master volume to 100%? -

I have been trying to use Qt5 multimedia to record audio with QAudioInput, however, when I see If QAudioInput is started, it increases the master volume of my sound device to 100%. How can I prevent QAudioInput from changing the master volume? My current development platform is Linux with PalsAdio (with flat audio disabled). How can I use QAudioInput : QAudioDeviceInfo device_info = QAudioDeviceInfo :: defaultInputDevice (); QAudio format format; Format.setSampleRate (44100); Format.setChannelCount (1); Format.setSampleSize (16); Format.setCodec ("Audio / PCM"); Format.setSampleType (QAudioFormat :: SignedInt); Format.setByteOrder (QAudioFormat :: LittleEndian); Std :: cout & lt; & Lt; Device_info.deviceName (). ToUtf8 (). ConstData () & lt; & Lt; Std :: endl; QAudioInput * default_device = new QAudioInput (device_info, format); QIODevice * default_io_device = default_device-> Start (); a QAudioInput.setVolume () method is not you I ...
Read more