368
368
WHERE t3.a=t1.a AND t3.a=t2.a;
369
369
id select_type table type possible_keys key key_len ref rows Extra
371
370
1 PRIMARY t1 eq_ref PRIMARY PRIMARY 4 test.t3.a 1
372
371
1 PRIMARY t2 ALL PRIMARY NULL NULL NULL 5 Using where; Using join buffer
373
373
2 DEPENDENT SUBQUERY t4 index NULL PRIMARY 4 NULL 7 Using where; Using index
375
375
(SELECT SUM(t4.a) FROM t4 WHERE t4.a IN (t1.b, t2.b))