1つのクエリで3つのテーブルにアクセスする

Question

あるテーブルから別のテーブルにデータをコピーしたい。どうやって？

$P_studentnumber=mysql_real_escape_string($_POST['studentnumber']); 
$P_subjectcode=mysql_real_escape_string($_POST['subjectcode']); 
$P_semester=mysql_real_escape_string($_POST['semester']); 

$sql "INSERT units INTO grades (units) FROM subjects WHERE subjectcode='$P_subjectcode'"; //<--THIS IS THE PART THAT I WOULD WANT TO ADD 

$sql="INSERT INTO grades (studentnumber,course, subjectcode, semester, instructorname, units) SELECT '$P_studentnumber', course, '$P_subjectcode', '$P_semester','$instructorname', 'units' FROM students WHERE studentnumber='$P_studentnumber'"; 

Answer 1

あなたは試すことができます：

INSERT table1(col1,col2) SELECT col1,col2 FROM table2 

Answer 2

はsite_constants_description_new SELECT site_constants_descriptionにこの

INSERTのようにしてみてください* site_language.site_language_id = site_constants_description_new.site_language_id site_constants_description_new、site_language FROM;。

歓声

Answer 3

SELECT...INSERT文の正しいSQL構文は次のとおりです。

INSERT INTO tableA (colA, colB, colC) 
SELECT colA, colB, colC 
FROM tableB 
WHERE colA = 'valueHere' -- this statement here is the condition 

列名（またはフィールド）が互いにと一致する必要があることを覚えておく必要があります。 INSERTに設定する列が一致しない場合は、INSERTでも構いませんが、ALIASを入力してください。

INSERT INTO tableA (colA, colB, colC) 
SELECT tableB.fieldA as colA, tableB.fieldB as colB, tableC.fieldC as colC 
FROM tableB INNER JOIN tableC ON tableB.fieldA = tableC.fieldA 
WHERE tableC.fieldA = 'valueHere' -- this statement here is the condition 

： JOINED表で同じ

INSERT INTO tableA (colA, colB, colC) 
SELECT fieldA as colA, fieldB as colB, fieldC as colC 
FROM tableB 
WHERE fieldA = 'valueHere' -- this statement here is the condition