COUNT (MySQL): verschil tussen versies
Naar navigatie springen
Naar zoeken springen
| Regel 1: | Regel 1: | ||
| − | + | Voorbeelden: | |
<pre> | <pre> | ||
| + | # Number of records in a table of view | ||
| + | ###################################### | ||
| + | # | ||
| + | select count(*) | ||
| + | from tmp; | ||
| + | </pre> | ||
| + | |||
| + | <pre> | ||
| + | # Aantal orders + totale omzet | ||
| + | ###################################### | ||
| + | # | ||
select sum(order_total),count(*) | select sum(order_total),count(*) | ||
from example.uc_orders | from example.uc_orders | ||
</pre> | </pre> | ||
| − | |||
| − | |||
<pre> | <pre> | ||
| + | # Lijst met unieke merken + aantal keer dat dat merk voorkomt | ||
| + | ############################################################# | ||
| + | # | ||
select | select | ||
| − | + | distinct brand, | |
| − | + | count(brand) as brand_count | |
| − | + | from | |
| − | + | device_tmp | |
| − | + | group by | |
| − | group by brand | + | brand |
| − | order by brand_count desc; | + | order by |
| + | brand_count desc; | ||
</pre> | </pre> | ||
Huidige versie van 12 apr 2020 om 13:31
Voorbeelden:
# Number of records in a table of view ###################################### # select count(*) from tmp;
# Aantal orders + totale omzet ###################################### # select sum(order_total),count(*) from example.uc_orders
# Lijst met unieke merken + aantal keer dat dat merk voorkomt ############################################################# # select distinct brand, count(brand) as brand_count from device_tmp group by brand order by brand_count desc;