That bosses, is many database query table is very meng, don't know how to begin, and what skills or understanding, the problem is such as Scott orcal users than the classic table query, are meng

CodePudding user response:

Can more fumble, practice makes perfect,

CodePudding user response:

What do you mean many tables associated query? This is the principle of relational database, such as more than 1 to 1, 1, can look at the aspects of theory,

CodePudding user response:

The building Lord said the question of specific,

CodePudding user response:

Left to join?

CodePudding user response:

Then watch more meng force advanced grammar, turned around and you will feel more table close the league too simple

CodePudding user response:

Want to realize the fuzzy query, add a combobox, extract the input Chinese strTemp, then insert the SQL statement, always have a question, make a half-day or not, please tell a great god!
((CComboBox *) GetDlgItem (IDC_COMBO2)) - & gt; GetWindowText (strTemp);
Str1. The Format (_T (" SELECT * FROM HY_STSC_A where STNM LIKE '% %' "+ strTemp +" "));
if (! TheApp. M_ado. Select (str1) MessageBox (theApp. M_ado. GetLastError ());

CodePudding user response:

You can use the join keyword, and other table join query

CodePudding user response:

Multi-table associated query is the key data divergence problem, that is when there is a one-to-many data, many-to-many time problem, affirmation is, of course, such data can not meet the specification, so we need to avoid as far as possible, as for how much table, qualifications do you have many branches, the complexity of the complex to simple to comb, can even use a temporary table to simplify the complexity of the association

CodePudding user response:

change numerous for brief, such as good a few tables, you can look at the two tables associated with what is in the table, since more than one table are linked article must have a line even n them together

CodePudding user response:

Understand the connection mode selection and scanning mode,

CodePudding user response:

Simplified to view and associated implementation

CodePudding user response:

Simple correlation using a line still, complex can only see, practising

CodePudding user response:

You ask the q is equal to white