sql-select

SELECT
    column_1,column_2,...
FROM
    table_1
[INNER|LEFT|RIGHT]JOINtable_2ONconditions
WHERE
    conditions
GROUPBYcolumn_1
HAVINGgroup_conditions
ORDER BYcolumn_1
LIMIToffset,length;

 

 

select语法

 

HAVING 和 WHERE 区别：

The MySQL HAVING clause is often used with the GROUP BY clause. When using with the GROUP BY clause, we can apply a filter condition to the columns that appear in the GROUP BY clause. If the GROUP BY clause is omitted, the HAVING clause behaves like the WHERE clause.

Notice that the HAVING clause applies the filter condition to each group of rows, while the WHERE clause applies the filter condition to each individual row.

 

subquery:

SELECT
    orderNumber, customerNumber, status, shippedDate
FROM
    orders
WHERE
    orderNumber IN (SELECT
            orderNumber
        FROM
            orderDetails
        GROUP BY orderNumber
        HAVING SUM(quantityOrdered * priceEach) > 60000);