Mysql and postgresql has '\' as the default escape syntax.
Hence when it tries to use the same to escape other characters , it fails as below.

com/sun/ts/tests/ejb/ee/pm/ejbql/where_clause/Client.java#whereTest27

Postgresql 8.2:

2007-06-04 16:29:44,312 DEBUG org.jboss.ejb.plugins.cmp.jdbc.JDBCEJBQLQuery.CustomerEJB#findCustomersByQuery28 Executing SQL: SELECT DISTINCT t0_c.ID FROM customerejb_table t0_c, aliasejb_table t1_a, aliasejb_customers_customerejb_aliases t3_c_aliases_RELATION_TABLE WHERE ((t1_a.ALIAS LIKE 'sh_ll' ESCAPE '\')) AND t0_c.ID=t3_c_aliases_RELATION_TABLE.CUSTOMEREJB AND t1_a.ID=t3_c_aliases_RELATION_TABLE.ALIASEJB
2007-06-04 16:29:44,531 ERROR org.jboss.ejb.plugins.cmp.jdbc.JDBCEJBQLQuery.CustomerEJB#findCustomersByQuery28 Find failed
org.postgresql.util.PSQLException: ERROR: unterminated quoted string at or near "'\')) AND t0_c.ID=t3_c_aliases_RELATION_TABLE.CUSTOMEREJB AND t1_a.ID=t3_c_aliases_RELATION_TABLE.ALIASEJB"
at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:1548)
at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:1316)
at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:191)
at org.postgresql.jdbc2.AbstractJdbc2Statement.execute(AbstractJdbc2Statement.java:452)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeWithFlags(AbstractJdbc2Statement.java:351)
at org.postgresql.jdbc2.AbstractJdbc2Statement.executeQuery(AbstractJdbc2Statement.java:255)
at org.jboss.resource.adapter.jdbc.WrappedPreparedStatement.executeQuery(WrappedPreparedStatement.java:236)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCAbstractQueryCommand.execute(JDBCAbstractQueryCommand.java:243)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCAbstractQueryCommand.execute(JDBCAbstractQueryCommand.java:144)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCFindEntitiesCommand.execute(JDBCFindEntitiesCommand.java:54)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.findEntities(JDBCStoreManager.java:613)
at org.jboss.ejb.plugins.CMPPersistenceManager.findEntities(CMPPersistenceManager.java:337)
at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.findEntities(CachedConnectionInterceptor.java:242)
at org.jboss.ejb.EntityContainer.find(EntityContainer.java:713)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.invocation.Invocation.performCall(Invocation.java:359)
at org.jboss.ejb.EntityContainer$ContainerInterceptor.invokeHome(EntityContainer.java:1126)
at org.jboss.ejb.plugins.AbstractInterceptor.invokeHome(AbstractInterceptor.java:105)
at org.jboss.ejb.plugins.EntitySynchronizationInterceptor.invokeHome(EntitySynchronizationInterceptor.java:203)
at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invokeHome(CachedConnectionInterceptor.java:189)
at org.jboss.ejb.plugins.AbstractInterceptor.invokeHome(AbstractInterceptor.java:105)
at org.jboss.ejb.plugins.EntityInstanceInterceptor.invokeHome(EntityInstanceInterceptor.java:136)
at org.jboss.ejb.plugins.EntityLockInterceptor.invokeHome(EntityLockInterceptor.java:76)
at org.jboss.ejb.plugins.EntityCreationInterceptor.invokeHome(EntityCreationInterceptor.java:45)
at org.jboss.ejb.plugins.CallValidationInterceptor.invokeHome(CallValidationInterceptor.java:56)
at org.jboss.ejb.plugins.AbstractTxInterceptor.invokeNext(AbstractTxInterceptor.java:125)
at org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(TxInterceptorCMT.java:350)
at org.jboss.ejb.plugins.TxInterceptorCMT.invokeHome(TxInterceptorCMT.java:161)
at org.jboss.ejb.plugins.SecurityInterceptor.invokeHome(SecurityInterceptor.java:145)
at org.jboss.ejb.plugins.LogInterceptor.invokeHome(LogInterceptor.java:132)
at org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invokeHome(ProxyFactoryFinderInterceptor.java:107)
at org.jboss.ejb.EntityContainer.internalInvokeHome(EntityContainer.java:521)
at org.jboss.ejb.Container.invoke(Container.java:981)
at sun.reflect.GeneratedMethodAccessor81.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)

Mysql 5.1

ERROR: Caught exception whereTest27: javax.ejb.FinderException: Find failed: com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''
'' at line 1
ERROR: javax.ejb.FinderException: Find failed: com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ''
'' at line 1
at org.jboss.ejb.plugins.cmp.jdbc.JDBCAbstractQueryCommand.execute(JDBCAbstractQueryCommand.java:260)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCAbstractQueryCommand.execute(JDBCAbstractQueryCommand.java:144)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCFindEntitiesCommand.execute(JDBCFindEntitiesCommand.java:54)
at org.jboss.ejb.plugins.cmp.jdbc.JDBCStoreManager.findEntities(JDBCStoreManager.java:613)
at org.jboss.ejb.plugins.CMPPersistenceManager.findEntities(CMPPersistenceManager.java:337)
at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.findEntities(CachedConnectionInterceptor.java:242)
at org.jboss.ejb.EntityContainer.find(EntityContainer.java:713)
at sun.reflect.GeneratedMethodAccessor120.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.jboss.invocation.Invocation.performCall(Invocation.java:359)
at org.jboss.ejb.EntityContainer$ContainerInterceptor.invokeHome(EntityContainer.java:1126)
at org.jboss.ejb.plugins.AbstractInterceptor.invokeHome(AbstractInterceptor.java:105)
at org.jboss.ejb.plugins.EntitySynchronizationInterceptor.invokeHome(EntitySynchronizationInterceptor.java:203)
at org.jboss.resource.connectionmanager.CachedConnectionInterceptor.invokeHome(CachedConnectionInterceptor.java:189)
at org.jboss.ejb.plugins.AbstractInterceptor.invokeHome(AbstractInterceptor.java:105)
at org.jboss.ejb.plugins.EntityInstanceInterceptor.invokeHome(EntityInstanceInterceptor.java:136)
at org.jboss.ejb.plugins.EntityLockInterceptor.invokeHome(EntityLockInterceptor.java:76)
at org.jboss.ejb.plugins.EntityCreationInterceptor.invokeHome(EntityCreationInterceptor.java:45)
at org.jboss.ejb.plugins.CallValidationInterceptor.invokeHome(CallValidationInterceptor.java:56)
at org.jboss.ejb.plugins.AbstractTxInterceptor.invokeNext(AbstractTxInterceptor.java:125)
at org.jboss.ejb.plugins.TxInterceptorCMT.runWithTransactions(TxInterceptorCMT.java:350)
at org.jboss.ejb.plugins.TxInterceptorCMT.invokeHome(TxInterceptorCMT.java:161)
at org.jboss.ejb.plugins.SecurityInterceptor.invokeHome(SecurityInterceptor.java:145)
at org.jboss.ejb.plugins.LogInterceptor.invokeHome(LogInterceptor.java:132)
at org.jboss.ejb.plugins.ProxyFactoryFinderInterceptor.invokeHome(ProxyFactoryFinderInterceptor.java:107)
at org.jboss.ejb.EntityContainer.internalInvokeHome(EntityContainer.java:521)