mysql合并字符串(sql地址合并)

未合并前sql:

SELECT
	ent.*,
	province.districtname AS addressprovinceName,
	city.districtname AS addresscityName,
	county.districtname AS addresscountyName 
FROM
	customer_enterprise ent
	LEFT JOIN base_districtinfo province ON province.id = ent.addressprovince
	LEFT JOIN base_districtinfo city ON city.id = ent.addresscity
	LEFT JOIN base_districtinfo county ON county.id = ent.addresscounty

结果sql:

SELECT
	ent.*,
	CONCAT(province.districtname,'—',city.districtname,'—',county.districtname) address
FROM
	customer_enterprise ent
	LEFT JOIN base_districtinfo province ON province.id = ent.addressprovince
	LEFT JOIN base_districtinfo city ON city.id = ent.addresscity
	LEFT JOIN base_districtinfo county ON county.id = ent.addresscounty