2017-03-06 30 views
-2

我有這個SQL,我想弄清楚放置WHERE子句的位置,因爲我有一些值要在第二列中進行過濾。何處放置WHERE關鍵字?

我要適應這樣的事情到下面的SQL:
WHERE是table2.column2 = '過濾器1' 或 '過濾器2'

create table practice_table 
AS SELECT table1.column1, table2.column2, count(table3.column3) ColumnAlias 
FROM practice1 table1 
JOIN practice2 table2 ON table1.table1ID = table2.table2ID 
JOIN practice3 table3 ON table1.table1ID = table3.table3ID 
GROUP BY table1.column1, t2.column2; 
+6

了'GROUP BY'之前。 'WHERE'子句緊跟在'FROM'子句之後。 –

回答

1
create table practice_table 
AS SELECT table1.column1, table2.column2, count(table3.column3) ColumnAlias 
FROM practice1 table1 
JOIN practice2 table2 ON table1.table1ID = table2.table2ID 
JOIN practice3 table3 ON table1.table1ID = table3.table3ID 
where table2.column2 in ('filter1','filter2') 
GROUP BY table1.column1, t2.column2;