优化器研究是否可以在搜索使用函数(例如)的查询时涉及可用的空间索引MBRContains ()或mbrwithin（）在在哪里条款。下面的查询查找在给定矩形中的所有对象:

mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))';MySQL>从Geom中选择FID，ST_ASTEXT（G） - > MBRContains（ST_GEOMFROMTEXT（@poly），g）;+ ----- + ------------------------------------------------------- + |FID |st_astext（g）|+ ----- + ------------------------------------------------------- + |21 |Linestring（30350.4 15828.8,30350.6 15845,30333.8 15845,30333.8 15845,30 ... | | 22 | Linestring（30350.6 15871.4,30350.6 15887.8,3034 15887.8，... | | 23 | Linestring（30350.6 15914.2,30350.6 15930.4,3035.6 15930.4,30334 15930.4，..。| | 24 | Linestring（30290.2 15823,30290.2 15839.4,30273.4 15839.4，... | | 25 | Linestring（30291.4 158662.4,30274.8 15882. ... | | 26 | Linestring（30291.6 15918.2,30291.6 15934.4,3027515934.4，... | | 249 | Linestring（30337.8 15938.6,30337.8 15946.8,30320.4 15946. | 1 | Linestring（30250.4 15129.2,30248.8 15138.4,30238.2 15138. | | | 2 | Linestring（30220.2 15122.8，30217.2 15137.8,30207.6 15136，... | | 3 | Linestring（30179 15114.4,30176.6 15129.4,30167 15128,3016 ... | | 4 | Linestring（30155.2 15121.4,30140.4 15118.6,30142 15109,30 ... | 5| Linestring（30192.4 15085,30177.6 15082.2,30179.2 15072.4，... | | 6 | Linestring（30244 15087,30229 15086.4,30229.4 15076.4,3024 ... | | 7 | Linestring（30200.6 15059.4,30185.6 15048.8，。.. | | | 10 | Linestring（30179.6 15017.8,30181 15002.8,30190.8 15003.6, ... | | 11 | LINESTRING(30154.2 15000.4,30168.6 15004.8,30166 15014.2, ... | | 13 | LINESTRING(30105 15065.8,30108.4 15050.8,30118 15053,3011 ... | | 154 | LINESTRING(30276.2 15143.8,30261.4 15141,30263 15131.4,30 ... | | 155 | LINESTRING(30269.8 15084,30269.4 15093.4,30258.6 15093,30 ... | | 157 | LINESTRING(30128.2 15011,30113.2 15010.2,30113.6 15000.4, ... | +-----+---------------------------------------------------------------+ 20 rows in set (0.00 sec)

使用解释要检查这个查询的执行方式:

mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))';MySQL>从Geom解释SELECT FID，ST_ASTEXT（G） - > MBRContains（ST_GEOMFROMTEXT（@poly），g）\ g ***************************** 1.行*************************** ID：1 Select_type：简单表：GEOM类型：Aruitay_key_key：G键：g key_len：32 ref：null行：50额外：使用设置中的1行（0.00秒）

检查如果没有空间索引会发生什么:

mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))';mysql >解释选择支撑材,ST_AsText从g (g)忽略指数(g) - > MBRContains (ST_GeomFromText (@poly), g) \ g  *************************** 1。row *************************** id: 1 select_type: SIMPLE table: geom type: ALL possible_keys: NULL key: NULL key_len: NULL ref: NULL rows: 32376 Extra: Using where 1 row in set (0.00 sec)

执行选择没有空间索引的语句产生相同的结果，但导致执行时间从0.00秒上升到0.46秒：

mysql> SET @poly = -> 'Polygon((30000 15000, 31000 15000, 31000 16000, 30000 16000, 30000 15000))';mysql> SELECT fid,ST_AsText(g) FROM geom IGNORE INDEX (g) WHERE > MBRContains(ST_GeomFromText(@poly)，g);+-----+---------------------------------------------------------------+ | 支撑材| ST_AsText (g ) | +-----+---------------------------------------------------------------+ | 1 | LINESTRING(30250.4 - 15129.2, 30248.8 - 15138.4, 30238.2 15136……| | 2 | linestring(30220.2 15122.8,30217.2 15137.8,30207.6 15136，…| | 3 | linestring(30179 15114.4,30176.6 15129.4,30167 15128,3016…| | 4 | linestring(30155.2 15121.4,30140.4 15118.6,30142 15109,30…| | 5 | linestring(30192.4 15085,30177.6 15082.2,30179.2 15072.4，…| | 6 | linestring(30244 15087,30229 15086.2,30229.4 15076.4,3024…| | 7 | linestring(30200.6 15059.4,30185.6 15058.6,30186 15048.8，…| | 10 | linestring(30179.6 15017.8,30181 15002.8,30190.8 15003.6，… | | 11 | LINESTRING(30154.2 15000.4,30168.6 15004.8,30166 15014.2, ... | | 13 | LINESTRING(30105 15065.8,30108.4 15050.8,30118 15053,3011 ... | | 21 | LINESTRING(30350.4 15828.8,30350.6 15845,30333.8 15845,30 ... | | 22 | LINESTRING(30350.6 15871.4,30350.6 15887.8,30334 15887.8, ... | | 23 | LINESTRING(30350.6 15914.2,30350.6 15930.4,30334 15930.4, ... | | 24 | LINESTRING(30290.2 15823,30290.2 15839.4,30273.4 15839.4, ... | | 25 | LINESTRING(30291.4 15866.2,30291.6 15882.4,30274.8 15882. ... | | 26 | LINESTRING(30291.6 15918.2,30291.6 15934.4,30275 15934.4, ... | | 154 | LINESTRING(30276.2 15143.8,30261.4 15141,30263 15131.4,30 ... | | 155 | LINESTRING(30269.8 15084,30269.4 15093.4,30258.6 15093,30 ... | | 157 | LINESTRING(30128.2 15011,30113.2 15010.2,30113.6 15000.4, ... | | 249 | LINESTRING(30337.8 15938.6,30337.8 15946.8,30320.4 15946. ... | +-----+---------------------------------------------------------------+ 20 rows in set (0.46 sec)