postgresql中,许多ddl语句支持if exists、if not exists。例如: postgres=# create table if not exists abce(); CREATE TABLE postgres=# drop table if exists abce; DROP
CREATE TABLE is a PostgreSQL command for creating tables. In Postgres, attempting to create a table that already exists will result in an error stating that the "relation already exists". To avoid such errors, the IF NOT EXISTS clause can be used with the CREATE TABLE command. Quick Outline...
strSQL :='CREATE TABLE IF NOT EXISTS'||TG_RELNAME||'_'||curMM||'( CHECK('||time_column_name||'>='''|| startTime ||'''AND'||time_column_name||'<'''|| endTime ||''')) INHERITS ('||TG_RELNAME||') ;';EXECUTE strSQL;--创建索引 strSQL :='CREATE INDEX'||TG_RELNAME|...
CREATE [ [GLOBAL|LOCAL] { TEMPORARY | TEMP } | UNLOGGED ]TABLE[IFNOT EXISTS ] table_name ( [ 有一些较老的版本,可能不支持IF NOT EXISTS语法,那么可以使用UDF实现类似的功能。 例如Greenplum: createor replacefunctionddl_ine(sqltext)returnsint2as$$declarebeginexecutesql;return0;-- 返回0表示正常ex...
IF ( tbExist = false ) THEN -- 创建子分区表 stm := yearStr||'-01-01 00:00:00.000'; etm := to_char(stm::timestamp + interval '1 year', 'yyyy-MM-dd HH24:mi:ss.ms'); sqlStr := 'CREATE TABLE IF NOT EXISTS '||TG_TABLE_NAME||'_'||yearStr|| ...
IF ( isExist = false ) THEN -- 创建子分区表 startTime := curMM||'01 00:00:00'; endTime := to_char( startTime::timestamp + interval '1 month', 'YYYY-MM-DD HH24:MI:SS'); strSQL := 'CREATE TABLE IF NOT EXISTS '||TG_RELNAME||'_'||curMM|| ...
DROPTABLEIFEXISTSyour_table_name; 如果表存在,则将其删除;如果表不存在,则不执行任何操作。 使用PL/pgSQL函数:可以编写一个PL/pgSQL函数来检查表是否存在,并在需要时抛出自定义错误。 代码语言:sql 复制 CREATEORREPLACEFUNCTIONcheck_table_exists(table_nametext)RETURNSbooleanAS$$DECLAREtable_exists...
2. PostgreSql 与常见的MySql, SqlServer 等数据库不同 假如创建表脚本是这么写的 CREATE TABLE IF NOT EXISTS dbo."SystemConfig"("Id"SERIAL PRIMARY KEY,"ConfigKey"VARCHAR(100),"ConfigValue"VARCHAR(500)NOTNULL); 注意: dbo是pgsql的schema名称, "SystemConfig" 是表名 ...
But what if a user wants to insert only those records that do not already exist in the selected table? How does Postgres deal with such situations? Well! In PostgreSQL, the INSERT statement doesn’t support the“IF NOT EXISTS”option. So alternatively, you can use the subquery to check th...
create table if not exists distlock(lockname text primary key,owner text not null,ts timestamptz not null,expired_time interval not null); 可选地,可以创建锁的历史表,每次锁的owner变更(主从角色切换)都会记录到历史表(distlock_history)中。