DROP TABLE IF EXISTS t1;
DROP TABLE IF EXISTS t2;
CREATE TABLE t1 (pk int primary key,c1 INT, c2 CHAR(100),c3 FLOAT);
SELECT * FROM t1 where pk = 1;
pk	c1	c2	c3
INSERT INTO t1 VALUES (1, null,null,0.0);
INSERT INTO t1 VALUES (2, 1,'',1.0);
INSERT INTO t1 VALUES (3, 2,'abcde',2.0);
INSERT INTO t1 VALUES (4, 100,'abcdefghij',3.0);
CREATE TABLE t2 (pk int primary key,c1 INT, c2 VARCHAR(100));
INSERT INTO t2 VALUES (1, 1,'abcde');
INSERT INTO t2 VALUES (2, 2,'abcde');
SELECT sb1,sb2,sb3 FROM (SELECT c1 AS sb1, c2 AS sb2, c3*2 AS sb3
FROM t1) AS sb WHERE sb1 > 1;
sb1	sb2	sb3
2	abcde	4
100	abcdefghij	6
SELECT AVG(sum_column1) FROM (SELECT SUM(c1) AS sum_column1 FROM t1
GROUP BY c1) AS t1;
AVG(sum_column1)
34.3333
DROP TABLE t1;
DROP TABLE t2;
CREATE TABLE t1 (pk int primary key, c1 INT, c2 VARCHAR(100),c3 FLOAT);
INSERT INTO t1 VALUES (1, null,null,0.0);
INSERT INTO t1 VALUES (2, 1,'',1.0);
INSERT INTO t1 VALUES (3, 2,'abcde',2.0);
INSERT INTO t1 VALUES (4, 100,'abcdefghij',3.0);
CREATE TABLE t2 (pk int primary key, c1 INT, c2 VARCHAR(100));
INSERT INTO t2 VALUES (1, 1,'abcde');
INSERT INTO t2 VALUES (2, 2,'abcde');
SELECT sb1,sb2,sb3 FROM (SELECT c1 AS sb1, c2 AS sb2, c3*2 AS sb3
FROM t1) AS sb WHERE sb1 > 1;
sb1	sb2	sb3
2	abcde	4
100	abcdefghij	6
SELECT AVG(sum_column1) FROM (SELECT SUM(c1) AS sum_column1 FROM t1
GROUP BY c1) AS t1;
AVG(sum_column1)
34.3333
DROP TABLE t1;
DROP TABLE t2;