编辑：
它是一个应该返回自动完成功能数据的查询.

>自动填充数据可以是text1或text2.
>完全匹配应该在顶部. int3是整数权重值,其中结果的顺序基于此.前两个查询用于识别完全匹配.
>接下来的两个查询用于识别近匹配.在哪里text1> ‘foo’和text1< 'fop'短语实际上等于WHERE text1 LIKE'foo％'.我这样写它是为了从索引中受益.
希望这可以帮助.

SELECT DISTINCT text1 as Key,'text1' as Source,int1 as Count,1000 as int3 
   FROM mytable 
   WHERE text1 = 'foo' 

UNION SELECT DISTINCT text2 as Key,'text2' as Source,int2 as Count,1000 as int3 
   FROM mytable 
   WHERE text2 = 'foo' 

UNION SELECT text1 as Key,MAX(int3) as int3 
   FROM mytable 
   WHERE text1 > 'foo' AND text1 < 'fop' AND Count < 4 
   GROUP BY Key 

UNION SELECT text2 as Key,MAX(int3) as int3 
   FROM mytable 
   WHERE text2 > 'foo' AND text2 < 'fop' AND Count < 4 
   GROUP BY Key 

ORDER BY int3 DESC,Count,Key LIMIT 0,15;

表结构是：

CREATE TABLE mytable (text1 TEXT,text2 TEXT,int1 NUMERIC,int2 NUMERIC,int3 NUMERIC);

它工作正常,但我需要微调性能.我尝试了不同的索引选项,并使用内置计时器检查了性能结果.

我发现的最好的索引选项是：

CREATE INDEX cmp1 ON mytable (text1 ASC,int1 ASC,int3 DESC);
CREATE INDEX cmp2 ON mytable (text2 ASC,int2 ASC,int3 DESC);

如果你能告诉我任何更好的索引选项或更好的SQL查询,我将很高兴.