我有一个问题 - 什么声明会在包含约3亿条记录的数据库表上有更好的表现?
这一个:
SELECT COL1, COL2, COL3
FROM
TABLE_1
WHERE COL4 IN ("SOMETHING1",
"SOMETHING2",
"SOMETHING3",
"SOMETHING4");
或者这个:
SELECT COL1, COL2, COL3
FROM
TABLE_1
WHERE (COL4 = "SOMETHING1" OR
COL4 = "SOMETHING2" OR
COL4 = "SOMETHING3" OR
COL4 = "SOMETHING4");