Introduzir uma tabela relacional
- currículo
- Tabela estudante
- Tabela curso
formato de consulta dois SQL introduzido
/* SQL查询的一般格式
SELECT [ALL | DISTINCT] [* | coulmnNameA,coulmnNameB,...]
FROM [tableName | viewName | (select语句)]
[AS 结果表的别名]
[WHERE 条件表达式x]
[GROUP BY coulmnName1 [HAVING 条件表达式y]]
[ORDER BY coulmnName2 [ASC | DESC]]
[LIMIT startRow,targetRows]
【各子句的处理顺序】FROM - WHERE - GROUP BY - HAVING - SELECT - ORDER BY
【关键词释义】
+ GROUP BY coulmnName : 将结果按 coulmnName 的值分组·，该属性列中值相等的分为一组
+ HAVING 条件表达式 : 若 GROUP BY 子句带HAVING短语，则： 只有满足指定条件的组才予以输出
*/
Três inquéritos de caso
Referências